Calculating Displacement in Elastic Collision of Pool and Croquet Balls

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Homework Help Overview

The discussion revolves around calculating the displacement of a pool ball after an elastic collision with a croquet ball. The problem involves understanding the dynamics of two colliding objects with given masses, initial distances, and accelerations, but lacks complete information regarding velocities and time intervals.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants explore how to derive the velocities of both balls from the provided information, questioning the sufficiency of the data given. There is discussion about using the time of acceleration and the implications of assuming no friction for the pool ball.

Discussion Status

The conversation is ongoing, with some participants attempting calculations based on conservation of momentum and kinematic equations. However, there is no consensus on the validity of the assumptions made or the accuracy of the results obtained, indicating a need for further clarification and exploration of the problem.

Contextual Notes

Participants note that the problem lacks sufficient information to determine the velocity of the croquet ball, as the duration of the force applied is not specified. Additionally, the assumption of no friction for the pool ball is under scrutiny.

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I swear, this is the last problem that I have.
Here it goes...
A pool ball having a mass of .65 kg experiences an elastic collision with a croquet ball having a mass of 1.38 kg. The pool ball had been rolling for 4.3 seconds, having covered a distance of 22.6 meters during that time. The croquet ball had been struck by a mallet only .80 seconds before the collision, and was given an acceleration of 12.6 m/s^2. How far from the point of impact will the pool ball be 1.9 seconds after the collision?

I'm lost on how to start the problem. I am sort of confused on how to solve for the displacement when not given the velocity/acceleration of both objects. I know that there's a way to get around that, but I can't see it. Can someone point out a formula that would help me solve this freakishly annoying problem.
 
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Ill posed

Among other things, the problem as stated does not provide enough information to establish the velocity of the croquet ball. We are told the force (acceleration) impressed, but not the duration of the force (.8 s is the delay between the strike and the future collision with the pool ball).

The velocity of the pool ball can be established from the given information only if we assume rolling with no friction.

-Beth
 
To find the velocity of the croquet ball, is that even possible, without the time? Could I use the .80 seconds as a point in time and base my info off of the collision?
 
I solved for the final velocity, and I got 10.51m/s. Then I used the conservation of momentum equation, and for the velocity of the croquet ball, I got 4.95m/s. So, to find the distance from the collision point, would I just use this kinematics equation, x=1/2Vft?

The answer that I got is 4.7025 meters. Is that close to being right?
 

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