A particle moves in a straight line with a constant acceleration. It changes its velocity from `10 ms^-1` to `20 ms^-1` while passing through a distance `135 m` in `t` seconds. The value of `t` is.

Options

A. 1.8
B. 12
C. 9
D. 10

Answer

C

Explanation

`u=10m//s,v=20m//s,S=135m`
`rArr (v^(2)-u^(2))/(2S)=a`
`rArr (400-100)/(2xx135)=a`
`a=(10)/(9)m//s^(2)`
`v=u=at`
`20=10+(10)/(9)t`
t=9