Question

A body starts rotating from rest and completes 10 revolutions in 4 s .Find its angular acceleration
A. `2.5 pi rad//s^(2)`
B. `5 pi rad//s^(2)`
C. `7.5 pi rad //s^(2)`
D. `10 pi rad //s^(2)`

Answer 1

Correct Answer - A
`theta=omega_(1)t+(1)/(2)alphat^(2)`
`therefore 20 pi= 0+(1)/(2)xxalphaxx16`
`therefore alpha=(20pi)/(8)=2.5 rad//sec^(2)`.