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

AI Thread Summary
The discussion revolves around a physics problem involving a railcart and a ball thrown inside it. The initial assumption was that the change in momentum of the railcart would be equal to mv when the ball was thrown. However, further analysis led to the conclusion that since the ball returns to the thrower at rest, the total momentum change of the system, including the railcart, is zero. Participants confirmed that because the ball is contained within the railcart, its motion does not affect the overall momentum of the railcart. Ultimately, the consensus is that the change in momentum of the railcart is zero.
sms14
Messages
5
Reaction score
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 ?
 
Physics news on Phys.org
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?
 
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
 
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.
 
can anyone verify if I am thinking along the right track?
 
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:
 
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.
 

Similar threads

Work done during a collision -- Change in Kinetic Energy & change in Momentum
Replies
1
Views
2K
Change in momentum when given the speed (not the velocity).
Replies
2
Views
3K
Impulse and Momentum: Ball and cart connected by a cord
Replies
24
Views
3K
Change in momentum, impulse force calculations
Replies
4
Views
2K
Momentum of ball on a pool table
Replies
12
Views
3K
Kinetic Energy & Momentum of a Ball released from Spring
Replies
6
Views
2K
Elastic collision -- Energy & Momentum
Replies
16
Views
2K
Magnitude of the change in momentum equation
Replies
13
Views
6K
Momentum Conservation in Collisions
Replies
5
Views
2K
Impulse and Momentum Conservation for a Frictionless Cart
Replies
5
Views
1K

Hot Threads

Recent Insights

Back
Top