Rotation

Two wheels of same masses M and radii R are joined coaxially so that the system can perform rolling motion on the ground.The system is released from the top of the inclined plane of inclination theta and height H.The system performs rolling motion on the inclined plane without slipping.The friction coefficient between the wheels and the inclined plane is mu.After some time the system reaches the bottom.Find the value of H for which the work done by the frictional force due to the inclined plane on the system is minimum during the complete motion.

8 Answers

1
swordfish ·

What's the answer?

11
jeetopper jee ·

@vinay work done 6Mgh/7 hai.

now what can we conclude about the minimum value of H
(kaha se liya hai yeh question)

23
qwerty ·

how is friction doing work wen the wheels are purely rolling ???? [7]

1
swordfish ·

Friction offcourse does work by providing torque (to increase the angular velocity of the wheel)

I got work done as 4Mgh/7
I don't know how we can find max or min. from this. The question seems wrong.

23
qwerty ·

u fogot the translational part ?
mgsinθ - f = ma

fR = mR2α

so f = mgsinθ2
Wf = ∫ f R dβ - f y
= f (Rβ - y )
β = angle rotated by wheel

y = distance moved by com of wheel
so Rβ = y

hence Wf = 0
i didnt understand why the question mentions pure rolling and gives μ also

1
swordfish ·

hmm....if that is the case then the question might be asking about rolling friction...which is not in the syllabus of JEE (as far as I know)

21
Shubhodip ·

i also got the answer zero///
@qwerty ; i think pure rolling is important to findout the value of frictional force///but mu is not required//

6
AKHIL ·

ya i think the work done by fricn in this case will be 0.

Your Answer

Close [X]