posted by jimmyjonas on .
7.A turntable reaches an angular speed of 33.3 rpm, in 2.1 s, starting from rest.
(a) Assuming the angular acceleration is constant, what is its magnitude?
b How many revolutions does the turntable make during this time interval?
V = 33.3rev/1min = 33.3rev/60s - 0.555rev/s.
a. a = (Vf - Vi) / t,
a = (0.555 - 0) / 2.1 = 0.264rev/s^2.
b. rev = 0.555rev/s * 2.1s = 1.17.
b) is incorrect above. You need to divide by 2 because the answer is the average velocity multiplied by time.
The correct answer is 0.585 revolutions.