What Causes a Sphere to Rotate on a Ramp with Negligible Friction?

AI Thread Summary
A sphere at rest on a ramp with negligible friction experiences only gravity and the normal force, both acting through its center of rotation. This means there is no net torque (τ=0) to initiate rotation. Without friction, the sphere will not rotate but will instead slide down the ramp. The discussion emphasizes that rotation is contingent upon the presence of friction. Therefore, without friction, the sphere simply slides without any rotation occurring.
Kiwiro0ls
Messages
12
Reaction score
0
If I have a sphere at rest on top of a ramp, if friccion is negligible, the only forces acting on it would be gravity and the normal force. Both of these go through it's axis of rotation which would be the spheres center. What would cause the rotation then so τ≠0?
 
Physics news on Phys.org
Kiwiro0ls said:
What would cause the rotation then so τ≠0?
What makes you think it would rotate?
 
I guess there's no rotation at all unless there's friccion? boo...
 
Right. Without friction, the sphere will just slide.
 

Thread '1:1 versus 2:1 Mechanical Advantage debate'

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...
View full post »

Thread 'Average velocity as a weighted mean'

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
View full post »

Thread 'Newton's first law?'

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?
View full post »

Similar threads

B Static friction needed for rolling without slipping
Replies
4
Views
2K
B Friction on pure rolling non deforming sphere?
Replies
3
Views
2K
B Rolling of non-deforming sphere on a non-deforming rough surface?
Replies
4
Views
2K
B Normal Force Discrepancy for Wedge Vs. Ramp
Replies
9
Views
3K
I Does a rotating accelerometer moving linearly measure linear velocity?
Replies
47
Views
4K
Does friction always result in energy loss?
Replies
3
Views
2K
A Cause of upward motion of a nutating top
Replies
1
Views
1K
Will a sphere rotate on a frictionless inclined surface?
Replies
23
Views
4K
I Confused about the axis of rotation in rotational motion w/o slipping
Replies
10
Views
3K
Rotating Sphere: Conceptual Question
Replies
10
Views
3K

Hot Threads

Recent Insights

Back
Top