Statement I: A disc is allowed to roll purely on an inclined plane as shown in Fig. A force `F` parallel to the incline and passing through the centre of the disc acts which remains constant during the motion.
It is possible that for certain values of `F`, the friction on the disc is acting along downward direction and for certain other values of `F`, the friction on the disc be acting along upward direction and there is no other possibility.

Statement II: The friction (if acting) will be static and not kinetic in nature.

Options

A. Statement I is True, Statement II is True, Statement ll is a correct explanation for Statement I.
B. Statement I is True, Statement II is True, Statement II is NOT a correct explanation for Statement I
C. Statement I is True, Statement II is False.
D. Statement I is False, Statement II is True.

Answer

D

Explanation

If `Fgtmgsintheta`, then friction on disc will be in downward directon and if `Fltmgsintheta`, then friction on disc will be in upward direction. If `F=mgsintheta`, then no friction will act on disc. Hence, Statement I is false.
Statement II is true because in pure rolling, friction can be either static or no friction.