NEET2019PhysicsRotational MotionActual
A disc of radius 20 ~cm and mass 1 / 2 ~kg is rolling on an inclined plane. Find out the frictional force such that disc performs pure rolling.
Options
- A5 2 3 N
- B5 3 2 ~N
- C5 2 ~N
- D5 2 3 ~N
Correct answer
B. 5 3 2 ~N
Step-by-step solution
Let m be the mass and R be the radius of the disc. m g -f=m a_ c m aligned & _ c m =I_ c m^ & f R= m R^2 2 ( a_ c m R ) aligned f= m a_ c m 2 or a_ c m = 2 f m So, m g -f=m ( 2 f m )f= m g 3 = 1 2 10 3 1 2 = 5 3 2 ~N