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Dr_bug
Nov6-09, 12:32 PM
1. The problem statement, all variables and given/known data

A 320 N sphere 0.20 m in radius rolls, without slipping, 6.0 m down a ramp that is inclined at 25° with the horizontal. What is the angular speed of the sphere at the bottom of the hill if it starts from rest?

2. Relevant equations
I sphere= (2/5)mr^2
atan=rα
v=rω

3. The attempt at a solution
I tried first to use F∆x=(1/2)*[(2/5)mr^2]ωf^2-0(zero because it starts from rest) but then i realize i don't have a mass and now i don't really know what to do. any helpful hints or suggestions would be appreicated

rock.freak667
Nov6-09, 12:47 PM
At the top, it only has potential energy mgh. At the bottom, the energy is entirely kinetic. Do you see why you don't need the mass?

Dr_bug
Nov6-09, 04:18 PM
so then can i just solve the eqn i was using and just ignore m?

rock.freak667
Nov6-09, 04:40 PM
so then can i just solve the eqn i was using and just ignore m?

No your equation is correct. Just what is the force F in F\Delta x?