The spin drier of a washing machine revolving at 15 r.p.s slows down to 5 r.p.s., while making 50 revolutions. Find (a) angular acceleration and(b) time taken.

The spin drier of a washing machine revolving at 15 r.p.s slows down t

1.	The spin drier of a washing machine revolving at 15 r.p.s slows down to 5 r.p.s., while making 50 revolutions. Find (a) angular acceleration and(b) time taken.
Answer» Solution :Here `omega_(0)=15 r.p.s = 30 pi rad s^(-1)` `ometa_(0)=5 r.p.s. = 10 pi rad s^(-1)` `theta = 50xx2pi=100 pi` Rad (a) Now, `omega^(2)-omega_(0)^(2)=2alpha theta` `THEREFORE (10 pi)^(2)-(30PI)^(2)=2alpha xx100 pi` or `alpha = -4 pi rad s^(-2)` (b) Also, `omega= omega_(0)+alpha t` `therefore 10 pi = 30 pi +(-4PI)XX t` or t = 5 s.