UMass Amherst PHYSICS 131 - Experiment 4 131 (4 pages)

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Conservation Lab Physics 131 Section L Thursdays 9 00 AM ILC S110 6 22 17 Abstract Newton s third law describes the conservation of momentum about how every action has an equal reaction which can be seen in the PAScar system to elastic collision when the momentum and energy upon release of one car is equal to that of the two cars after a collision Along with the loss of kinetic energy when two separate objects are collided forming one system in the inelastic experiment Questions Answers 1 In case of elastic collisions what would happen if m1 is much much larger than m2 Conversely what would happen if m1 is much much smaller than m2 2 points When m1 is much much larger than m2 it s velocity is slowed after the collision but it continues moving in the same direction it was released in while if m1 is much much smaller than m2 after the collision it is moved in the opposite direction of where it was originally traveling 2 In your lab manual the equations 4 4 and 4 5 give the final velocities of the two objects in terms of the initial velocity and the masses Now are the final velocities you found in your trials consistent with these equations Show your work 2 points Table 1 Data assortment of masses velocity KE and P of trials Equation 4 4 0 28 0 500 Equation 4 5 22 2 28 250 500 Doesn t work our results show that V2 28 the equation says V2 22 Our results for equation 4 4 are in line with what the equation says we should have gotten 0 and our results equal 0 However for equation 4 5 the equation shows we should have gotten 22 for V2 but our results show our V2 as being 22 3 Using the velocities make a TABLE for the momentum and kinetic energy of each PAScar before and after collision Calculate the percent difference between TOTAL final and initial momenta and kinetic energy in each trial and comment on the conservation of momentum and conservation of energy 2 points Mass proportion P before g m s P after g m s Percent difference Pbefore Pafter Pb efore 100 m1 m2 elastic 70 55 21 42 m1 m2 elastic 200 180 10 m1 m2 elastic 120 115 4 1 m1 m2 inelastic 105 5 80 21 95 Mass proportion KE before J KE after J Percent difference KEbefore KEafter KEbefore 100 m1 m2 elastic 19 6 12 1 38 26 m1 m2 elastic 80 61 35 23 31 m1 m2 elastic 57 6 41 7 27 6 m1 m2 inelastic 42 025 12 8 69 5 4 In the inelastic collision why do you need to measure only one final velocity 2 points You only measure one final velocity because the cars are stuck together making them one unit travelling at the same velocity so there is only one because the two cars