The displacement of a particle moving in a straight line is given by `x=2t^2+t+5` where x is expressed in metre and t in second. The acceleration at t = 2 s is

Options

A. `4 ms^(-2)`
B. `8 ms^(-2)`
C. `10 ms^(-2)`
D. `15 ms^(-2)`

Explanation

Distance covered in 2 s is,
`s=ut+1/2g t^2=u(2)+1/2xx10xx2^2=2u+20`
Distance covered in next is,
`"S"^2=[u(3)+1/2xx10(3)^2]-(2u+20)`
`3u+45-2u-20`
`"S"^1=u+25`
Since,`s=s^1`
`2u+20=u+25`
`u=5`
`s=2xx5+20=30m`