· A billiard ball collides head-on with billiard ball at rest. · Sketch a position vs. time graph for each ball, include position before the collision, once the collision occurs and after the collision.

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Pre-Lab Questions

· A billiard ball collides head-on with billiard ball at rest.

· Sketch a position vs. time graph for each ball, include position before the collision, once the collision occurs and after the collision.

 

· What can be said about the conservation of momentum for the collision? Explain your answer.

·

 

· Write down the total momentum for two marbles of mass, m, both moving at velocity, v . What is the kinetic energy of the system?

 

· When you drop two marbles at once, why doesn’t only one marble come off the end twice as fast? Write down the kinetic energy of one marble with mass m and velocity 2v and compare this to your answer in Experiment 1 Post Lab Question 4 to check.

Note: Assume the collisions are perfectly elastic.

 

 

 

Experiment 1: Conservation of momentum

Data Sheet

Table 1. Collision Data- Moving and Stationary Marbles

Number of Flicked Marbles Number of Stationary Marbles Number of Marbles that Leave the Runway
1 4  
2 3  
3 2  
4 1  
     

 

Table 2. Collision Data- Moving Marbles

Number of Marbles on Right Side of Runway Number of Marbles on Left Side of Runway Number of Marbles that Leave the Right Side of the Runway Number of Marbles that Leave the Left Side of the Runway
1 1    
1 2    
1 3    
1 4    
2 2    
2 3    

 

Post-Lab Questions

· What kind of collision is exhibited by the marbles in this experiment and why?

 

· When one marble hit the end of the line of marbles, how many shot off the other end? Describe the momentum of the set of marbles before and after the collision (assume elastic collisions).

·

 

· How did the speed of the marble that comes off the end of the line change as you increased the speed of the marble that travels down the chute? Use what you know about the conservation of momentum to describe what is happening.

 

· What happened when you sent two marbles down the runway? Is this what you predicted? Explain why or why not.

·

 

· How did the result change when both marbles were moving toward each other before the collision?

 

· What do you predict would happen to two marbles after a collision if you slowly rolled a marble down the runway and then flicked a second marble faster in the same direction?