Physics
posted by TLP .
Two pulleys are connected by a belt that causes one pulley to rotate (via friction) as it is driven by the first pulley. The belt turns around the pulleys without slipping on either one. rA is 10.0 cm and rB is 25.0 cm. If wheel A starts from rest and increases its rate of rotation at 1.5 rad/s2, find the time needed for wheel B to reach 75.0 rpm.

rb/ra=tb/ta
rb/ra=2.5
so when wheel B is 75rpm, wheel A is 75/2.5= 30 rpm=30*2PI/60 rad/sec
time:
wf=alpha*t
t= wf/alpha=(30*2PI/60)/1.5 seconds