Physics (Rotation)
posted by M .
In Fig. 1028, wheel A of radius rA is coupled by belt B to wheel C of radius rC. The angular speed of wheel A is increased from rest at a constant rate α. Find the time needed for wheel C to reach angular speed ω assuming the belt does not slip. (Hint: If the belt does not slip, the linear speeds at the two rims must be equal.) State your answer in terms of the given variables.
FIGURE: imgur . com/QxZR5. gif
(remove spaces and paste)
I tried:
(rA/rC)*α
and
ωC/αC
but said it was wrong.

((Rc)/(ra) * omega)/alpha