 # Q   A solid cylinder of mass m and radius r is rolling on a rough inclined plane of inclination θ. The coefficient of friction between the cylinder and incline is m. Then        (A)    frictional force is always mmg cos θ        (B)    friction is a dissipative force        (C)    by decreasing θ, frictional force decreases        (D)    friction opposes translation and supports rotation  Badiuddin askIITians.ismu Expert
148 Points
12 years ago

Dear Mainak N = mgcosx

maximum frictional force  f= μN =μmgcosx

this friction force will not always act .it is the maximum possible frictional force.

a= (mgsinx -f)/m

for pure rollinr  α =a/r

and torque f.r  = mr2/2 α

f  =ma/2

=m/2 (mgsinx -f)/m

f = mg/3 sinx

by decresing x frictional force decreses

so  d option is correct

Please feel free to post as many doubts on our discussion forum as you can.
If you find any question Difficult to understand - post it here and we will get you
the answer and detailed  solution very  quickly.

All the best.

Regards,