A 24 inch string is wrapped around the 1/8 inch radius axis of a yo yo. Starting from rest the yo yo descends with a constant angular acceleration of 4 rad/second squared. How long will it take the string to completely unwind?

Answer 1

Basic equation required:
Arc = rθ
S=ut+(1/2)at²

4 rad/s²
≡ 4r inch/s²
=(1/2) inc/s²

initial velocity, u =0
a = 0.5 in/s²
24 inches = 0*t + (1/2)at²
t=sqrt(2*24/0.5)
=sqrt(96)
=9.8 s