The displacement of an obuect attached to a spring and executing simple harmonic motion is given by `x=2xx100^(-2) cos pit` metre. The time at which the maximum speed first occurs is.

Options

A. (a) `0.25 s`
B. (b) `0.5 s`
C. (c )0.75 s`
D. (d) `0.125 s`

Answer

B

Explanation

(b) Here, `x=2xx10^(-2) cos pi t`
:. `v=(dx)/(dt)=2xx10^(-2) pi sin pi t`
For the first time, the speed to be maximum,
`sin pi t` or, `pit=sin(pi)/2`
`rArrpit=(pi)/2 or, `t=1/2=0.5 sec`.