The velocity-time graph of a particle moving along a straight line is shown is . The rate of acceleration and deceleration is constant and it is equal to `5 m s^(-2)`. If the a average velocity during the motion is `20 m s^(-1)`, Then .
The value of `t` is.

Options

A. `5 s`
B. `10 s`
C. `20 s`
D. `5sqrt 2s`

Answer

a

Explanation

Average speed `=20 m s^(-2)`
`(Total distance )/(Total time) =20`
.
`rArr ("Area of graph")/(20 +t) =20`
` rArr (1)/(2) (20+t+ 20 -t )xx 5t =20 (20+ t) rArr t=5 s`.