Assuming the turntable is circular, its circumference is
(2 π) x (its radius) .
That's the distance covered by a point on its rim during every complete revolution.
The distance covered by the same point during 45 revolutions is
(45) x (2 π) x (radius).
So we can write . . .
Speed of the point = (45 rev/min) · (2 · π · 8 cm / rev)
Speed = (720 π) cm/minute
Speed = 12π cm/second
Speed = 37.7 cm/sec
Speed = 0.377 m/s
