Question

A small block of mass is placed on a rough

horizontal disc at a distance from its axis. The

disc starts rotating from rest at time =

0 about its axis with constant angular

acceleration . The coefficient of friction

between the disc and the block is .


a. If the block does not slide over the disc,

find friction force acting on the block at

time .


b. At what time does the block start to slide

over the disc?​

Answer 1

Explanation:

Here, the table is a circular table and so the frictional force is equivalent to the centripetal force of the table as it moving with a constant angular velocity.

A centripetal force is a force that makes a body follow a curved path. Its direction is always orthogonal to the velocity of the body and towards the fixed point of the instantaneous center of curvature of the path.

The equation for centripetal force using angular velocity is:

F

c

=mω

2

R