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

`v^2 = u^2 +2as`
`rArr a = (v^2 - u^2)/(2S) = (400-100)/(270) = 10/9 m//s^2`
Now , v = u + at
`rArr t = (v-u)/(a) = (20-10)/(10//9) = 9 sec.`