Calculating Displacement in Elastic Collision of Pool and Croquet Balls

In summary, the problem involves an elastic collision between a pool ball and a croquet ball, where the pool ball has a mass of 0.65 kg and the croquet ball has a mass of 1.38 kg. The pool ball is rolling for 4.3 seconds before the collision, covering a distance of 22.6 meters. The croquet ball is struck by a mallet 0.80 seconds before the collision and is given an acceleration of 12.6 m/s^2. It is not possible to find the velocity of the croquet ball without knowing the duration of the force. Assuming no friction, the velocity of the pool ball can be calculated as 10.51 m/s and the velocity
  • #1
Tabe
42
0
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.
 
Physics news on Phys.org
  • #2
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
 
  • #3
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?
 
  • #4
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?
 

1. How do pool balls transfer energy during a collision?

During a collision between two pool balls, energy is transferred from the cue ball (striking ball) to the object ball (struck ball). This energy transfer occurs through a combination of kinetic energy, rotational energy, and frictional energy.

2. What factors affect the outcome of a pool ball collision?

The outcome of a pool ball collision can be affected by a variety of factors such as the speed and angle of the cue ball, the mass and composition of the balls, the surface friction of the table, and the presence of any spin on the cue ball.

3. Why do pool balls sometimes move in unexpected directions after colliding?

This can happen due to a phenomenon known as "squirt" or "cue ball deflection". When a cue ball is struck with sidespin, it can cause the cue ball to deviate from its expected path after contact with the object ball. This is due to the cue stick compressing and bending slightly upon impact, resulting in an uneven force being applied to the cue ball.

4. Is the collision between two pool balls completely elastic?

No, the collision between two pool balls is not completely elastic. Some of the energy is lost due to friction between the balls and the table, as well as the balls themselves. This is why the balls eventually come to a stop, rather than continuing to bounce around indefinitely.

5. How do professionals use physics to their advantage in pool?

Professional pool players use their understanding of physics to predict and control the paths of the cue ball and object ball during a shot. They also use techniques such as "English" or sidespin to manipulate the path of the cue ball and achieve more precise shots. Additionally, understanding the physics of collisions can help players anticipate and plan for the movements of multiple balls on the table.

Similar threads

  • Introductory Physics Homework Help
Replies
10
Views
1K
  • Introductory Physics Homework Help
Replies
15
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
34
Views
666
  • Introductory Physics Homework Help
Replies
16
Views
2K
  • Introductory Physics Homework Help
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
7
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
10
Views
1K
  • Introductory Physics Homework Help
Replies
4
Views
324
Back
Top