Good Ol' Rotation - from the Dark Knight

The acceleration a of the supporting surface required to keep the centre G of the circular cylinder in a fixed position during the motion if there is no slipping between the cylinder and the support will be :________________

Ans : 2g sin@

3 Answers

21
eragon24 _Retired ·

net force acting on the cylinder parallel to incline
for motion of cylinder
fr=frictional force between cylinder and support
ma'=mgsin@-fr

COM of cylinder is stationary that means a'=d2xdt2=0(assuming x axis along incline)

so,

fr=mgsin@

torque on cylinder abt point G=frR=(mR2/2)α
fr=mRα/2=ma/2
ma/2=mgsin@
a=2gsin@

1
Bicchuram Aveek ·

Excellent Eragon, ridden the dragon well.

But i've one little doubt here.

Could we have done it by a procedure where we first take the block's acceleration as a...and a pseudo acceleration a for the Cylinder ??

And why are we considering that the cylinder and the block move together such dat der's a common acceleration a ???? If it's so then there should be no force of friction between the cylinder and the block !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

19
Debotosh.. ·

friction is actually zero !
rath sir concept, again !

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