Question

two particles are initially moving with angular momentum L1 and L2 in a region of space with no external torque. A constant external torque T then acts on one particle, but not on the other particle, for a time interval ∆t. What is the change in the total angular momentum of the two particles?​

Answer 1

Explanation:

Using

dt

dL

=τ

Thus ΔL=τ(Δt)

Also, L=Iw

⟹ΔL=IΔw

Δw=

I

τ(Δt)

If w

i

=0, thus w

f

=Δw

Now KE

R

=

2

1

Iw

f

2

=

2I

(τΔt)

2

ΔKE

R

=

2I

(τΔt)

2

only when w

i

=0.