A gramophone record takes 5s to reach its constant angular velocity of 4(pi) rads-1 from rest. Find its constant angular acceleration.
-
A.
0.4(pi) rads-2 -
B.
0.8(pi) rads-2 -
C.
1.3(pi) rads-2 -
D.
20.0(pi) rads-2
Correct Answer: Option B
Explanation
From the radiation:
V = +at, and if it starts from N & T, U = 0
And for angular motion, W = O + at
4R = aχ5
∴ a = (4a)/5 = 0. 8(pi) rads-2