Question

A uniform disc of mass m and radius R is rolling down a rough inclined plane which makes an angle 30 with the horizontal. If the. Cofficent of static and kinetic friction are each equal to u and the only forces, acting are gravitational and frictional, then the magnitude if the frictional force acting on the disc is A)mg/3 upward B)mg/3 downward C)mg/6 up D)mg/6 down

Answer 1

Answer:

Forceequationis

mgsin30

0

−f=ma....(1)

Torqueequationis

fR=

2

1

mR

2

(

R

α

)⇒f=

2

ma

⇒from(1)

2

mg

−

2

ma

=ma

⇒a=

3

g

⇒f=

6

mg

andits

directionisupwards