I need to find the angular acceleration of a hollow ball rolling (without slipping) on a ramp, given the angle of the ramp theta, the mass and radius of the ball, and gravity and other physical constants, but not frictional constants. The catch is, torque is applied to the ball that, if it were unopposed by gravity, would roll it up the hill, as below.

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I don't know how to deal with the extra torque, and I'm not given information about the direction the ball will roll. Can anyone help?


closed as off-topic by Aaron Stevens, ZeroTheHero, John Rennie, rob Nov 27 '18 at 14:12

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  • $\begingroup$ Is the disc rolling without slipping? $\endgroup$ – Aditya Garg Nov 26 '18 at 20:38
  • $\begingroup$ @AdityaGarg Yes, I'll specify that in an edit $\endgroup$ – JL123 Nov 26 '18 at 20:41
  • $\begingroup$ What are your thoughts on this so far? Have you drawn a free body diagram showing the forces acting on the ball? $\endgroup$ – Chet Miller Nov 26 '18 at 21:03
  • $\begingroup$ @ChesterMiller Yes, my diagram includes frictional force, normal force, gravitational force, and the torque being applied. $\endgroup$ – JL123 Nov 26 '18 at 21:07
  • $\begingroup$ @ChesterMiller I also have the idea that there is a torque created by gravity and friction which opposes the applied torque, but I don't know how to deal with that numerically. $\endgroup$ – JL123 Nov 26 '18 at 21:12