Question

Doubt:

Answer 1

@Vincent-Lyon.Fr

I have no idea which principle to apply here.

Answer 2

@Mashy

Answer 3

\[F \Delta t = mV_f - mV_i \\ \tau \Delta t = I \omega_f - I \omega_i \\ \tau = Fh\]

knock yourself out :D

Answer 4

I have not done the problem, but I am sure Mashy's method (impulses) is the right one.
Answer is D.

Answer 5

I see. I am new to applying impulse concept in rotation. Let me try it.

Answer 6

I got

\[hF \delta T=2/5 mr^2\]

Substituting F dT

hmv=2/5mr^2w

w=5hv/r^2

Where did I go wrong?

Answer 7

that is correct :P

Answer 8

There is no option with my answer??

Answer 9

You have forgotten to divide by 2 when solving for w, but the equation hmv=2/5mr^2w is correct.

Answer 10

Oh that was a silly mistake! Thanks! :)