Week+3

=Day 10=

**Lesson 19**
__**In Class**__


 * ** Power **
 * Power is the rate of energy dissipated
 * P=W/t
 * W is often change in the GPE or KE
 * P=(F*d)/t=F*t
 * Watts (W)
 * Horsepower=746 W
 * ** Momentum **
 * Newton: quantity of motion
 * Books: m*v
 * Symbol: (p)
 * Units: kg*m/s
 * Impulse (J) = m*change in v
 * Units: N*s=kg*m/s

__**At Home**__
 * **The Impulse Momentum Change Theorem**
 * Momentum
 * Momentum is the mass of an object times its velocity so if either of them changes, so does momentum and if there is no velocity then there is no momentum, also it includes the direction the object is headed in.
 * Momentum and Impulse Connection
 * Impulse is equal to the momentum where impulse is decided into the amount of time in a collision and the amount of force in the collision.
 * [[image:http://www.physicsclassroom.com/Class/momentum/u4l1b3.gif width="247" height="178" align="center"]]
 * Real World Application
 * The different variables determines the actions and changes that take place.

Does any one remember [|Bill Nye the Science Guy]?

**Lesson 20**
__**In Class**__ > B= bullet cart > A= target cart
 * Momentum cannot be created or destroyed but transferred
 * Total momentum of a system remains constant, as long a system remains constant (ignoring friction during collision)
 * **Lab-__Elastic Collision__**
 * **Objective**: A small sports car hits a heavy truck in a collision. What factors determine the outcome for the passengers of the two vehicles? Which driver will sustain worse injuries? Why?
 * **Hypothesis**: The mass and velocity of both object will determine the out come for the passengers. the Sports car driver will sustain more injury, because the mass of the sports car is less the truck so it is propelled faster.
 * **Materials**
 * two carts
 * a track
 * four .5 kg weights
 * two unknown weights
 * several smaller weights
 * **Data and observations:**
 * Trial # || Mass of Bullet Cart (kg) || Mass of Target Cart (kg) || Applied force (qualitative only) || Description and Observations (qualitative) ||
 * 1 || .5 || .5 || Very gently || B hit A, B stayed still and A bounced back against the wall, and bounced forward, hitting B so B slowly slid back to the other wall ||
 * 2 || .5 || .5 || Gently || “1”, only faster ||
 * 3 || .5 || .5 || Medium || “2”, only faster ||
 * 4 || 1 || 1 || Very gently || “1”, only they moved more slowly and because A didn’t bounce back as hard, ||
 * 5 || 1 || 1 || Gently || “1” only a tiny bit slower ||
 * 6 || 1 || .5 || Very Gently || A moved faster than B as it bounced back ||
 * 7 || 1 || .5 || Gently || B bounces a little when hit back by A after A bounces ||
 * 8 || 1.5 || .5 || Gently || After A bounces back it barely bounces B in the middle ||
 * 9 || .5 || 1 || Gently || B bounces back ||
 * Mystery Car Weight # || Estimated/ Experimental (kg || Real (kg) ||
 * 1 || 0.75 || 0.7 ||
 * 2 || 1.23 || 1.2 ||
 * **Questions**
 * 1) The collisions in this could be the same as in bumper-cars, since the velocity and mass can vary but can also be the same. The stationary aspect of the experiment can be found in billiards.
 * 2) The observation of how carts interact gave us great insight into collision since when we got the unknown mass our estimates where at most .05 kg off.
 * 3) The results from the collision with objects of the same mass was the same, but an increase in bullet mass made the target go father and an increase in the target made the target go not as far.
 * 4) Momentum is related to inertia since it is mass times velocity.
 * 5) The eagle has greater momentum since it has more mass and momentum is dependent of the mass.
 * 6) The transfer of momentum occurs when two objects collide and when there is a velocity change in both.
 * 7) If a car hit a skate border, then the car's momentum will be transferred to the skate border, propelling them in the same direction the car was traveling.
 * **Conclusion**
 * If both the sports car and truck have the same speed in a head-on collision, then the car will go in the opposite direction it was traveling and the truck will continue to go forward.
 * The bullet cart may not been delivered with the same amount of force every time so the observed results could be off.
 * To re-due the lab, a variety pf springs could be used to ensure constant force.


 * **Lab-__Inelastic collision__**
 * **Objective**: How does the initial momentum relate to the final momentum of the cart?
 * **Hypothesis**: The more initial momentum there is, the more final momentum there will be.
 * **Reasoning**: Since there is no loss of momentum and there are essential only two moving object since the bullet and target cart stick to gather the increase in initial momentum would cause the increase in the final momentum.
 * **Data:**

__**At Home**__
 * Mass of Bullet Cart (kg) || Mass of Target Cart (kg) || Speed of Bullet Cart (m/s) || Speed of Target cart (m/s) || Combined masses (kg) || Final Velocity of both carts (m/s) ||  || Initial Momentum kgm/s || Final Momentum kgm/s || % Differences ||
 * 0.5 || 0.5 || 0.083 || 0 || 1 || 0.04 ||  || 0.0415 || 0.04 || 3.61% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || 0.066 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.031 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.033 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.031 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">6.06% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || 0.083 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.041 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0415 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.041 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.20% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || 0.072 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.034 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.036 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.034 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">5.56% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || 0.083 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.04 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0415 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.04 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">3.61% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || 0.053 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || 0.033 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.053 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0495 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">6.60% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || 0.047 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || 0.029 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.047 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0435 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">7.45% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || 0.063 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || 0.04 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.063 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.06 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">4.76% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || 0.038 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || 0.022 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.038 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.033 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">13.16% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || 0.073 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || 0.049 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.073 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0735 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.68% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.102 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || 0.033 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.051 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0495 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">2.94% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.08 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || 0.025 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.04 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0375 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">6.25% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.125 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || 0.041 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0625 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0615 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.60% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.091 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || 0.029 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0455 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0435 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">4.40% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.125 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || 0.041 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0625 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0615 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.60% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.051 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">2.5 || 0.029 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0765 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0725 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">5.23% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.047 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">2.5 || 0.026 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0705 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.065 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">7.80% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.092 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">2.5 || 0.055 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.138 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.1375 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.36% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.052 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">2.5 || 0.029 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.078 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.0725 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">7.05% ||
 * <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1.5 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">1 || 0.05 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: center;">0 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">2.5 || 0.028 ||  || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.075 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">0.07 || <span style="color: #000000; display: block; font-family: 'Times New Roman',serif; font-size: 16px; text-align: right;">6.67% ||
 * **Calculations**
 * Find the initial momentum of the bullet cart for each trial.
 * m i *v i =M i
 * .5*.083=M i
 * M i=0.0415 (kg*m/s)
 * Find the initial momentum of the target cart for each trial
 * m i *v i =M i
 * .5*0=M i
 * M i=0 (kg*m/s)
 * Find the sum of the initial momenta of the two carts for each trial.
 * m 1 *v 1 +m 2 *v 2 =M i
 * .5*.083 + .5*0=M i
 * M i=0.0415 (kg*m/s)
 * Find the final momentum of the combined carts for each trial.
 * m f *v f =M f
 * 1*.04=M f
 * M f=0.04 (kg*m/s)
 * Find the percent difference between the initial momentum (calc 3) and the final momentum (calc 4).
 * (abs(M f- M i)/avg (M f+ M i))*100%
 * (abs(.04 - .0415 )/avg (.04 + .0415 ))*100%
 * Percent Difference: 3.61%
 * Question
 * 1) The initial and final where almost the same and as initial momentum increased so did final momentum. The initial momentum is slightly larger than the final momentum.
 * 2) Inelastic collisions are where the object stick together like a bullet getting lodged in a block, we know this since both the initial and final momentum are the same and both objects have the same velocity.
 * 3) Elastic collisions is when two objects hit and then bounce off like in baseball between the bat and ball, we know this because the individual momentum of each object changes and the final velocity are different.
 * 4) The initial momentum must be distributed to all the 15 of the billiard balls so there is not much of a momentum in all the billiard balls, since the initial momentum is just the one ball and the final momentum is the sum of all sixteen balls.
 * Conclusion
 * The officer can look at how much the two cars travel travel and their masses to determine there initial speed. The conservation of momentum is that friction is ignored and all the momentum that was initially there has to go somewhere.
 * One experimental error is that there was a slight friction on the tract so some of the momentum was lost.
 * To re-due this, it hard to say, but having a tract that had even less friction like an ice surface would probably give better results for the conservation of momentum.
 * To re-due this, it hard to say, but having a tract that had even less friction like an ice surface would probably give better results for the conservation of momentum.

>> =Day 14=
 * **Law of Momentum Conservation**
 * Law of Action Reaction
 * In a collision this means that since all the energy in a system remains the same, the momentum is transferred between objects.
 * Momentum Conservation Principal
 * Since all the momentum is conserved the beginning momentum equals the final momentum though the direction may differ.
 * [[image:http://www.physicsclassroom.com/Class/momentum/u4l2b5.gif width="327" height="90" align="center"]]
 * [[image:http://www.physicsclassroom.com/Class/momentum/u4l2b4.gif width="324" height="83" align="center"]]
 * Isolated Systems
 * Objects in the system can still be acted upon by an unbalanced force, so the conservation of momentum takes place where there is no external forces.
 * Momentum conservation in collisions
 * With the equation and the knowledge that all momentum in a system is not lost, the change in the momentum of objects can be determined.
 * Momentum Conservation in Explosions
 * In explosions the momentum equals out. So the momentum of every object that was moved by an exposion when added together taking the direction into account, it equals zero.

** Lesson 26 **
__** In Class **__


 * ** Lab-Spring and Mass **


 * ** Part A: **
 * Objective: What is the relationship between the force that a spring exerts on a mass and the distance the string stretches?
 * Hypothesis: As the spring stretches the more force exerts on the mass increase proportionally.
 * Reasoning: The principal of potential spring energy should be close to this, because both involve springs.
 * Data
 * [[image:C7.PNG]]
 * [[image:C8.PNG]]
 * [[file:Lab Mass on Spring Part A.xlsx]]
 * ** Part B: **
 * Objective: What is the relationship between oscillation + the mass?
 * Hypothesis: As the mass increase the period should increase.
 * Reasoning: The heavier mass will stretch the string more meaning more time will be needed to pull the mass up.
 * Data:
 * [[image:C9.PNG]]
 * [[image:C10.PNG width="581" height="334"]]
 * [[file:Lab Mass on Spring Part B.xlsx]]
 * Conclusion
 * From the graph it can be seen that there is an inverse square relationship.
 * We used T=2pi(sqrt(m/k), so the coefficient should be the spring force constant from part A.
 * The constant here is 3.09 when in the previous one it was 3.22 meaning there is a discrepancy.
 * The error is most likely due to human reaction time when measuring the period.
 * Another error is that the measurement of the displacement could be off since it was not the most accurate way of measuring total displacement.
 * Another error is that the measurement of the displacement could be off since it was not the most accurate way of measuring total displacement.

__** At Home **__


 * ** Vibrations-SQ3R **
 * What are vibrations and what are terms associated with it?
 * Vibrations are the back and forth movements of objects that occurs in nature.
 * Resting position is when an object is not moving and can be said that it is at a state of equilibrium.
 * Forced vibration is when an object is placed into vibration by an outside force.
 * Dampening is the dissipating of energy over time by a vibration.
 * What is periodic motion?
 * Is a regular, repeating motion. The position of it will go from one point to another and back at a constant rate.
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l0b1.gif width="467" height="119"]]
 * How is the period of an object and its frequency related and what are they?
 * Period is the time it takes to complete a single cycle.
 * Frequency is the amount of cycles completed in a single cycle
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l2b1.gif width="314" height="40"]]
 * What forces and energy are present in a pendulum? How does it relate to vibrations?
 * There is tension and gravitational forces.
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l0c3.gif caption="external image u10l0c3.gif"]]
 * There is potential and kinetic energy.
 * A pendulum swings at a constant rate meaning it vibrate.
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l0c8.gif width="399" height="262"]]
 * How are springs related to force and periodic motion?
 * The force of a spring can be calculated **Fspring = -k•x** where k is the specific spring force that depends on the spring and x is how much it is stretched or compressed.
 * A spring stretches and compresses at a periodic rate. To find it use ** T = 2•π•(m/k).5 **

** Gotta love those [|pendulums]. **



** Lesson 27 **
__** In Class **__


 * ** Waves **
 * Require mediums to travel
 * Medium
 * Material that carries the wave
 * Made of particles that can interact
 * Transverse
 * Particles oscillate perpendicular to the direction of the wave travel
 * Crest
 * Max displacement
 * Trough
 * Min Displacement
 * Wavelength
 * The distance between a point on the wave and the same point on the next wave
 * Amplitude
 * Distance from equilibrium to crest or trough
 * Period
 * Time for one complete cycle
 * Wave Speed
 * Wavelength per time
 * Depends only on the medium
 * Frequency
 * How many waves passes in one second
 * ** When mediums change **
 * Speed changes
 * Frequency remains the same
 * ** Reflection **
 * Th bouncing of of an object
 * Angle of incident + angle of reflection
 * Boundary
 * Where medium changes
 * ** Refraction **
 * When a wave meets an object and changes direction
 * Wave changes speed
 * ** Diffraction **
 * When a wave meets an object or opening and the wave bends around to spread into the space behind it.
 * Bigger opening = less diffraction
 * shorter the wavelength = less diffraction
 * ** Interference **
 * When two waves over lap to form a new wave
 * ** Longitudinal **
 * particles oscillate parallel to the direction of the wave
 * Region of compression
 * High compression
 * Particles are closer together
 * Rarefaction
 * Low pressure region
 * Particles are spread out
 * ** Electromagnetic **
 * Needs no medium
 * ** Lab **
 * Objective
 * To find the relationship between wave speed and frequency.
 * To find the relationship between wave speed and wavelength.
 * To distinguish between transverse and longitudinal waves.
 * Hypothesis
 * The speed of the wave and the frequency have no connection.
 * The speed of a wave and the length of a wave has no relation.
 * Transverse wave will move like a sine or cosine function while longitudinal will be a straight line
 * Reasoning
 * Prior knowledge that the speed of light is constant and that the frequency and wavelength are inversely proportional.
 * It is the definition of the two different wave
 * Data
 * [[image:F5.PNG]]
 * [[image:F6.PNG]]
 * Observation
 * The longitudinal pulse travels to the other-side and back like the transverse wave but parallel with the motion.
 * Questions
 * 1) The average time for the set of three are all close together that the difference can be the result of human error.
 * 2) There was a small change but it could be due to experimental error.
 * 3) Though there was a change in the speed, there was supposed to be no change like the 5 meter length.
 * 4) The speed of the waves were close enough that the difference was experimental error even though the amplitude changed.
 * 5) The speed of the snaky spring was faster with the 10 meter distance, while the speed for the slinky was faster with the 5 meter difference.
 * 6) The medium changes since the springs are stretched causing there to be a variation in the density of the spring. The wavelength changed. The speed changed since the data clearly shows a change in speed.
 * 7) Snaky spring was faster with the 10 meter distance while the slinky was faster in the 5 meter distance. This is due to a difference of material/medium.
 * 8) Transverse waves changes in displacement while the longitudinal wave compresses and and stretched
 * Analysis:
 * The hypothesis has been confirmed.
 * The speed stayed relatively the same when amplitude is being change
 * As the speed changed as the wavelength changed.
 * It showed how the stretching of a spring changes the medium and the speed of a wave
 * The errors from the lab is the r esult of human reaction time.

__**A t Home**__
 * **The Nature of a Wave-SQ3R**
 * Where can waves be found?
 * Waves can be seen in water.
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l1a2.gif width="193" height="200" align="center"]]
 * They can be seen in the motion of a slinky.
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l1a1.gif width="275" height="181" align="center"]]
 * In math class with sine and cosine functions.
 * Light and micro waves.
 * What is a wave and what is related to it?
 * A wave is a repeating disturbance through a medium.
 * A disturbance is a change in an object from rest to a different position to rest again.
 * A pulse is a single disturbance that moves through a medium.
 * A wave is a repeating and periodic disturbance through a medium.
 * A medium is a substance carries a wave.
 * A wave is the interaction between particles.
 * What types of waves are there?
 * Transverse waves are waves where the particles move perpendicular to the motion of the wave
 * Longitudinal is the movement of a particles parallel to the wave.
 * Sound waves are types of the longitudinal particles.
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l1c5.gif width="406" height="160" align="center"]]
 * Surface waves are where a substances in a medium make a circular motion.
 * Electromagnetic waves can move through vacuums.
 * Mechanical waves are waves that need a medium to travel.
 * **Properties of a wave?-PQ3R**
 * What are the parts of a wave?
 * Transverse waves
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l2a1.gif width="283" height="125" align="center"]]
 * Crest is the max positive displacement.
 * Trough is the max negative displacement.
 * Amplitude is the maximum displacement from the rest position.
 * Wavelength is the length of one complete cycle.
 * Longitudinal wave
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l2a2.gif width="332" height="119" align="center"]]
 * Compression is the maximum density of particles in a medium
 * Rarefaction is the minimum density of particles in a medium
 * How is the frequency measured?
 * The frequency is measured in number of vibrations in a set time. Units are Hertz
 * How is energy and amplitude related?
 * The amplitude is the amount of energy carried by a wave.
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l2c1.gif width="65" height="26" align="center"]]
 * What affects the speed of a wave in a string?
 * The tension of the string affects it.
 * How do you calculate the speed of a wave?
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l2e2.gif width="146" height="34" align="center"]]
 * **Speed = Wavelength • Frequency**
 * **Behavior of Waves-PQ3R**
 * What is a boundary? Fixed end and open end difference.
 * A boundry is when one medium ends and another begins.
 * Fixed end reflex the wave back onto the medium inverted.
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l3a2.gif width="333" height="123" align="center"]]
 * Open end reflex the wave, but does not invert.
 * [[image:http://www.physicsclassroom.com/Class/waves/u10l3a4.gif width="332" height="119" align="center"]]
 * Going from less dense to more dense materials both transfers a wave and reflects an inverted wave


 * [[image:http://www.physicsclassroom.com/Class/waves/u10l3a6.gif width="366" height="257" align="center"]]
 * What is reflection, refraction, and diffraction?
 * Reflection is when a wave meets a barrier and changes direction
 * Refraction is when the wave enters a new medium and changes direction.
 * Diffraction is when a wave changes direction as it passes through an opening.
 * What are waves interference?
 * When two waves meet in the same medium interact.
 * <span style="color: #404040; font-family: 'Times New Roman','serif'; font-size: 16px;">Constructive interference is when two waves with the same shape and direction meet, the amplitudes add together these locations are called anti-nodes.
 * <span style="color: #404040; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal;">Destructive interference is when two waves with the same shape and but different direction meet, the amplitudes cancel each other are nodes.
 * <span style="color: #404040; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal;">When waves are not equal, then there is a slight depletion in the larger wave.
 * <span style="color: #404040; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal;">After the waves meet they continue at their original amplitude.
 * <span style="color: #404040; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal;">What is the Doppler effect?
 * <span style="color: #404040; font-family: 'Times New Roman','serif'; font-size: 16px; line-height: normal;">Its the perception of a change in the wavelength and frequency due to the moving of a source of sound.