Ok here is the problem A hollow spherical shell with mass 2.50kg rolls without slipping down a slope that makes an angle of 30.0 degrees with the horizontal.(adsbygoogle = window.adsbygoogle || []).push({});

> Find the acceleration a_cm of the center of mass of the spherical shell.

> Take the free-fall acceleration to be g=9.80m/s^2.

> I got 24.2068 but again I was wrong

- I though it was mgsin(theta) was it not?

> Find the frictional force acting on the spherical shell.

Im not sure but wouldnt it be coefficient of friction (which I do not know) times the normal force (which would be the answer to the above I think?)

Another problem is :

A circular hoop of mass m, radius r, and infinitesimal thickness rolls without slipping down a ramp inclined at an angle theta with the horizontal. View Figure

> http://session.masteringphysics.com/problemAsset/1010918/22/MAD_ia_2_v1.jpg

> What is the acceleration a of the center of the hoop?

> Express the acceleration in terms of physical constants and all or some of the quantities m, r, and theta.

and to be honest I have no clue whatsoever on how to do that problem :/ man Im beginning to hate physics I dont understand it at all

:uhh:

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# Homework Help: Mastering physics :/

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