A sphere of mass m is rotated about its axis by an angular velocity `omega` and lowered gently on an inclined plane as shown in figure. Then initally

Options

A. the centre of mass of sphere accelerates upwards.
B. the centre of mass of shpere accelerates downwards
C. the lowest point of contact accelerates upwards.
D. the lowest point of contect accelerates downwards.

Answer

C

Explanation

`mg sin theta - f = ma`
`"mg" (sqrt3)/(2) - mu mg cos 60^(@) = ma`

`"mg" (sqrt3)/(2) - (sqrt3)/(2) mg = ma`
`a = 0`
`tau_(COM) rArr f R = I alpha`
`alpha = (fR)/(I)`
a point contact is towards up the plane.