Friction: Snooker Ball Mass & Speed Calculation

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    Friction Mechanics
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Discussion Overview

The discussion revolves around a physics problem involving the motion of a snooker ball, specifically focusing on the effects of friction and the calculation of distance traveled after bouncing off a cushion. The scope includes mathematical reasoning and conceptual clarification regarding rolling and sliding motion.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant presents the initial conditions of the problem, including mass, initial speed, and coefficient of friction.
  • Another participant requests a detailed solution to the problem.
  • Concerns are raised about the applicability of the coefficient of friction, noting that a snooker ball primarily rolls with minimal sliding, which complicates the calculation.
  • One participant provides calculations using Newton's laws, arriving at a speed when the ball hits the cushion and subsequently calculating the distance it travels after the bounce.
  • A later reply acknowledges a mistake in the previous calculations and presents a revised distance based on the new understanding of the ball's speed after the bounce.
  • Participants discuss the implications of rolling versus sliding, with one asserting that pure rolling would imply no friction, while others express uncertainty about how to handle this aspect in their calculations.

Areas of Agreement / Disagreement

Participants express disagreement regarding the role of friction in the context of rolling versus sliding motion. There is no consensus on how to approach the problem, particularly in determining the extent of sliding during the ball's motion.

Contextual Notes

Limitations include the lack of clarity on the proportion of the ball's motion that involves sliding versus rolling, which affects the applicability of the coefficient of friction in the calculations.

Who May Find This Useful

This discussion may be useful for students studying mechanics, particularly those interested in the dynamics of rolling objects and the effects of friction in practical scenarios.

Shah 72
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A snooker ball of mass 0.4kg is struck towards a cushion from 0.8m away with speed 3m/s. The surface of the snooker table has a coefficient of friction of 0.3. When the ball bounces from the cushion its speed is reduced by 20%. Find how far from the cushion it stops.
 
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show your work on this problem, please
 
I have a basic problem with this. A snooker ball primarily rolls with only a slight amount of sliding. The coefficient of friction only applies to the sliding. To answer this you would have to know what part of the motion was sliding and I see no way to determine that.
 
skeeter said:
show your work on this problem, please
m=0.4kg, u=3m/s, coefficient of friction =0.3
By using Newtons law
F=m×a
-0.3×4=0.4a
a=-3m/s^2,
By using v^2=u^2+2as, v=2.05m/s when the ball hits the cushion
The speed decreases by 20%, so 2.05×0.8=1.64m/s. Again using v^2=u^2+2as, I get s=0.25m
 
skeeter said:
show your work on this problem, please
Oh sorry I had done a silly mistake. So initial velocity is 3 and when it hits the cushion, the final velocity is 2.05 m/s , this is reduced by 20% so now u= 1.64 m/s and v=0 ( as the ball stops) so the distance will be 0.448m
 
Country Boy said:
I have a basic problem with this. A snooker ball primarily rolls with only a slight amount of sliding. The coefficient of friction only applies to the sliding. To answer this you would have to know what part of the motion was sliding and I see no way to determine that.
Thanks! I could work out the solution.
 
I am glad. How did you handle the "rolling versus sliding" problem?
 
Country Boy said:
I am glad. How did you handle the "rolling versus sliding" problem?
I just guessed rolling. Iam still in A levels so probably my textbook doesn't get into so much detail.
 
If there were pure rolling, there would be NO friction!
 
  • #10
Country Boy said:
If there were pure rolling, there would be NO friction!
Yeah you are right.
 

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