A particle moves in a straight line with a constant acceleration. It passing through a distance 135 m in t second. The value of t (in second) is

Options

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

Answer

B

Explanation

`upsilon^(2)=u^(2)+2as`
`a=(upsilon^(2)-u^(2))/(2s)=((20)^(2)-(10)^(2))/(2xx135)=(300)/(270)=(10)/(9)ms^(-2)`
From first equation of motion
`upsilon=u+at rArr t(upsilon-u)/(a)=(20-10)/(10//9)=(10)/(10//9)=09s`