Physics Question-Please Show Work!?

Question

A phonograph record has an initial angular speed of 33 rev/min. The record slows to 10 rev/min in 1.7 s. What is the record's average angular acceleration during this time interval?

Answer 1

Av. angular acceleration
= [(10/60) - (33/60)]/1.7 rev/s^2
= - 0.2255rev / s^2 or - 1.420radians / s^2

Answer 2

Av. angular acceleration
= (10*60 - 33*60)/1.7 rev/s^2
= - 811.8 rev / s^2