Rotating pool table, calculating max ang. velocity

AI Thread Summary
To calculate the maximum angular velocity for a rotating pool table without the balls moving, a coefficient of static friction of 0.3 is assumed, with table dimensions of 50 inches by 100 inches. The calculated angular velocity is approximately 9.7 RPM based on the formula for radial acceleration. However, it's noted that this calculation only applies to flat objects and does not account for rolling friction. Rolling friction must be considered to prevent the balls from rolling, and it can be assessed by lifting the table until the balls begin to move. Accurate calculations require a comprehensive understanding of both static and rolling friction dynamics.
osumecheng
Messages
1
Reaction score
0
Hi,
I am trying to calculate how fast you could rotate a pool table (at constant angular velocity) without the balls moving.
Assumptions used: coeffecient of static friction=0.3
table dimensions: 50in.X100in.
So the farthest distance from the center is 111.8 in.
I came up with about 9.7 rpm by setting radial acceleratio=R*omega=coeff. friction*g
Can anyone check me on this, not sure if I did it right. Thanks!
 
Physics news on Phys.org
The balls would roll. Your calc would work only for a flat object.
You need to include "rolling friction" (Which is not really friction) to keep the balls from rolling. The coefficient of static friction does not enter your calculation, except to determine when the balls would start to skid.
Rolling friction can be determined by lifting the table until the balls start to roll.
 
The rope is tied into the person (the load of 200 pounds) and the rope goes up from the person to a fixed pulley and back down to his hands. He hauls the rope to suspend himself in the air. What is the mechanical advantage of the system? The person will indeed only have to lift half of his body weight (roughly 100 pounds) because he now lessened the load by that same amount. This APPEARS to be a 2:1 because he can hold himself with half the force, but my question is: is that mechanical...
Hello everyone, Consider the problem in which a car is told to travel at 30 km/h for L kilometers and then at 60 km/h for another L kilometers. Next, you are asked to determine the average speed. My question is: although we know that the average speed in this case is the harmonic mean of the two speeds, is it also possible to state that the average speed over this 2L-kilometer stretch can be obtained as a weighted average of the two speeds? Best regards, DaTario
Some physics textbook writer told me that Newton's first law applies only on bodies that feel no interactions at all. He said that if a body is on rest or moves in constant velocity, there is no external force acting on it. But I have heard another form of the law that says the net force acting on a body must be zero. This means there is interactions involved after all. So which one is correct?
Back
Top