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. 12
B. 9
C. 10
D. 1.8

Answer

B

Explanation

For constant acceleration
`v^(2)=u^(2)+2as`
`(20)^(2)=(10)^(2)+2xxaxx135`
`a=(300)/(270)ms^(-2)`
As `v=u+at`
`20=10+axxt`
10 = at
`10=(300)/(270)xxt` ltbtgt t = 9 sec