A disc is rotated about its axis with a certain angular velocity and lowered gently on a rough inclined plane as shown in Fig., then

Options

A. a)It will rotate at the position where it was placed and then will move downwards
B. b) It will go downwards just after it is lowered
C. c)It will go downwards first and then climb up
D. d) It will climb upwards and then move downwards

Answer

A

Explanation

Here kinetic friction force will balance theforceof gravity. So it will rotate at its initial position and will not move up or down. As its angular velocity becomes zero (friction also beomes zero), it will move downwards.