The angular speed of a larger pulley wheel (radius=15cm) is 50 rev./min. Find the angular speed of the smaller wheel (radius=6cm).

Answer 1

Assuming the two wheels are linked by a belt, then the tangential velocities are equal, i.e. the products of angular speed and radius are equal:
ω1(r1)=ω2(r2), or
ω2=ω1(r1/r2)

Answer 2

125rev/min