The length of second's hand in watch is `1 cm`. The change in Velocity of its tip in 15 seconds is

Options

A. zero
B. `(pi)/(30sqrt2) cm//s`
C. `(pi)/(30) cm//s`
D. `(pi sqrt2)/(30) cm//s`

Answer

D

Explanation

In 15 second's hand rotate through `90^(@)`.
Change in velocity `|vec Deltav|2 v sin (theta//2)`
`=2(romega) sin (90^(@)//2)=2xx1xx(2pi)/(T)xx(1)/sqrt2`
`(4pi)/(60sqrt2)=(pisqrt2)/(30) " "[AsT=60 s]`.