In the situation given, a force `F` is applied at the top of sphere. Study following statements.

Options

A. The sphere will move faster if friction is absent.
B. The sphere will move faster if friction is present
C. The sphere will move with same velocity irrespective the friction.
D. Friction supports the motion

Answer

B, D

Explanation

`F+f=mg` …….i
`FR-fR-2/5mR^(2) a/R` ………ii

After solving these two equations we get the frictional force is positive. This implies that friction supports the motion.