physics question

Question

A phonograph record with a diameter of 30.0 cm rotates 33.5 times per minute.

What is the velocity of a point on its rim? (answer is 0.527 but I keep getting it wrong)

Answer 1

Remember your answer needs to be in m/s

Diameter = 30 cm

Radius = 30/2 = 15 cm = 0.15 m

Circumference = 2πr (with r = 0.15)

In 60 seconds (1 minute) it rotates 33.5 times, so a distance of 33.5 x 2 x π x r , so in 1 second it rotates a distance of

33.5 x 2 x π x r / 60 which should give the right answer (r = 0.15)

[ I get 0.5262 using an exact value of π ]