What is the Change in Momentum of the Railcart in this Problem?

In summary, the problem involves a person sitting in a moving railcart and throwing a ball against the wall of the cart, which then bounces off and is caught by the person. The question is asking for the change in momentum of the railcart, with options ranging from 0 to 2mv. After considering the momentum of the ball, the person, and the final resting position of the ball, it is determined that the correct answer is 0, as there is no change in momentum of the railcart in this scenario.
  • #1
sms14
5
0

Homework Statement



one of my homework problems

you are sitting in a railcart which is moving forward. In your hand is a ball...you throw the ball against the wall of the railcart, and it bounces off of the wall and you catch it...the ball has mass m and was thrown with velocity v...which of the following shows the change in momentum of the rail cart

a. 0 b. mv c. 2mv d. none of above

Homework Equations



mv + mv = mv + mv


The Attempt at a Solution



i was thinking the answer is b because if the ball bounces off, it had to have affected the rail cart with a value of mv ?
 
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  • #2
sms14 said:

The Attempt at a Solution



i was thinking the answer is b because if the ball bounces off, it had to have affected the rail cart with a value of mv ?


Was there any change in momentum when you threw the ball? What about when you catch the ball? You are part of the system aren't you?
 
  • #3
well, i assume I'm part of the system...and i guess the final momentum of the ball is 0 since i caught it??..i just am having trouble understanding the problem and the logistics of it
 
  • #4
actually...now that i think about it..i think the answer is 0 because if the person and ball are located within the railcart, then ultimately...if the ball was thrown and returns at rest...there was no momentum change so the change in momentum of the railcart must be zero.
 
  • #5
can anyone verify if I am thinking along the right track?
 
  • #6
sms14 said:
actually...now that i think about it..i think the answer is 0 because if the person and ball are located within the railcart, then ultimately...if the ball was thrown and returns at rest...there was no momentum change so the change in momentum of the railcart must be zero.

10/10 :biggrin:
 
  • #7
sms14 said:
actually...now that i think about it..i think the answer is 0 because if the person and ball are located within the railcart, then ultimately...if the ball was thrown and returns at rest...there was no momentum change so the change in momentum of the railcart must be zero.

Good job. You didn't get derailed. You are on the right track now.
 

1. What is momentum?

Momentum is a physics concept that describes the tendency of a moving object to continue moving in the same direction and at the same speed unless acted upon by an external force. It is equal to the mass of an object multiplied by its velocity.

2. How is momentum calculated?

Momentum is calculated by multiplying an object's mass by its velocity. The formula for momentum is: p = m * v, where p is momentum, m is mass, and v is velocity.

3. How does momentum change?

Momentum can change when an object experiences an external force. This force can either increase or decrease the object's velocity, which in turn affects its momentum.

4. What is the law of conservation of momentum?

The law of conservation of momentum states that in a closed system, the total momentum before and after a collision or interaction must be equal. This means that momentum is conserved and cannot be created or destroyed.

5. How is change in momentum related to force?

According to Newton's second law of motion, force is equal to the change in momentum over time. This means that the greater the force acting on an object, the greater the change in its momentum will be. In other words, a larger force will cause a greater acceleration and thus a greater change in momentum.

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