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In order to set up a project that conserves momentum we put Kelsey on roller blades and she threw a ball. As she threw the ball fowards she rolled backwards. The medicine ball had enough of a force to move Kelsey backwards, and in this recoil problem. the forward and backward momentums are equal. In order to solve for momentum we will set up a bomber problem with the ball moving forward. With the measured dispalcement in the X, displacement in the Y, known accelerations in both directions, and Velocity in the X = 0, we are able to solve for time, thus Velocity in the X. After finding Velocity in the X and measuring mass, we are able to use the equation, P=mv to solve for momentum. In the backwards direction Kelsey moved a shorter distance in the X, but her mass was greater. Her larger mass and smaller velocity has a momentum equal to the ball's smaller mass and larger velocity.

Safety Precautions: -use safe rollerblading techniques (helmet or pads) -make sure there is ample space when throwing ball

Equipment: -Kelsey -Rollerblades -7 pound ball -Measuring tape -Calculator

Procedure 1. Kelsey stands on roller blades holding a 7lb medicine ball. Her momentum is 0 because she has no velocity (she is standing still). 2. Kelsey throws the ball forward. 3. As the ball moves forward, Kelsey rolls backward. 4. We measured the distance in the X direction from where Kelsey started and the ball landed. 5. We knew the initial velocity of the ball in the Y direction is 0, the acceleration in the Y is --9.8, and the displacement in the Y is -1.2319. We used ViVfDAT to solve for the time. We used the time found in the Y to find the velocity in the X. 6. We multiplied the velocity found in the X direction (from step 5) with the mass of the medicine ball to find the momentum. 7. Regarding Kelsey, we measured the distance in the X she traveled backward and knew her final velocity is 0. 8. In order to solve for acceleration, we solved for the force of friction which equaled the force applied. 9. Kelsey stood on rollerblades and pushed against a scale until she was moving back at a constant rate. What the scale read was 2lbs which equaled the force applied. 10. Since the force applied equaled Kelsey's mass (on rollerblades) multiplied by her acceleration, we used the known Fa and mass to solve for acceleration. 11. This acceleration, along with the known Vf and displacement in the X, we used to solve for Vi. 12. To solve for momentum, we multiplied Kelsey's mass (on rollerblades) by her initial velocity. 13. The two momentums of Kelsey and the ball should be equal because this is a recoil problem. 14. Our momentums were 14.34 and 14.10, which only had a 1.7% error. 15. We concluded that our momentum was conserved. Momentum Total Momentum Before Recoil = 0.0 kg/m.s

Total Momentum After Recoil = 0.24 kg/m.s

Percent Error = 1.7 %

Before M V P

Kelsey and Ball 53.47 kg 0 m/s 0 kg/m.s

After M V P

Kelsey 50.35 kg .285 m/s 14.34 kg/m.s

Ball 3.12 kg 4.l5187 m/s 14.10 kg/m.s

Conclusion: Momentum Conserved!! Momentum was conserved because after converting the m * v= p equation the before and after momentums were very close to being equal, thus meaning that momentum was conserved.

Since the momentums before and after were not exactly the same there was human error involved when we did our experiment. This could have possibly come from our measurements delta y or our delta x. When Kelsey released the ball there is a possibility that she could have lifted the ball higher than we had measured, which would have changed our data. We also had trouble weighing the rollerblades, therefore, Kelsey's mass with the rollerblades could be not as accurate as we would have hoped.