CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
Question

A disc of mass 2 kg and radius 0.2 m is rotating with an angular velocity of 30 rad/s. What is the angular velocity if the mass of 0.25 kg is put on the periphery of the disc?

Open in App
Solution

Angular momentum in the absence of any external torque remains constant,
i.e. L=Iω=constant
I1ω1=I2ω2
12Mr2ω1=12(M+2m)r2ω2(i)
Here, M=2 kg,m=0.25 kg,r=0.2 m
ω1=30 rad/s
Hence, we get after putting the given values in Eq. (i)
=12×2×(0.2)2×30=12×(2+2×0.25)(0.2)2×ω21.2=0.05ω2ω2=24 rad/s
Because we have to balance the weight, we cannot simply put 0.25 kg mass on one side of the disk we have to either distribute the mass equally on the entire disk or we have to add equal mass on the opposite end of the disk.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Realistic Collisions
PHYSICS
Watch in App
Join BYJU'S Learning Program
CrossIcon