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Old Oct 25th 2018, 02:01 AM   #1
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Rolling Ball

Greeting to all

I need small help to solve this problem .
I have the answers but i could not reach it .

Ans : (a) h = 2.7 R , (b) Fx = -(20/7)mg , Fy = - mg

Best regards
Razi

Note : this problem is not homework !
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Old Oct 25th 2018, 03:27 AM   #2
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The key to this problem is to see that point at which the sphere fails to complete the loop is not when it's speed is zero ... but when mg = m omega squared r , omega here is the rotational speed around the loop ....r is not the r in the question

We have another omega which is the rotation of the sphere itself about it's center of mass ..

At the point of failure there is inertial energy stored in the spin of the sphere , as well as energy stored by virtue of it's velocity

It's an energy balance problem ...( height of mass of sphere at failure is 2R-r)
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Old Oct 25th 2018, 04:40 AM   #3
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Dear oz93666

Thank you sooooo much for your idea , i did it and i have solved the problem

Best regards
Razi
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