In figure shown, the graph shows the variation of acceleration of body with time `t`. The velcocity of the body at `t = 0` is zero. The velocity of the body at `t = 30 s` is.

Options

A. `30 m//s`
B. `20 m//s`
C. `40 m//s`
D. none

Answer

A

Explanation

Area upto `30 s` : = `(1)/(2) xx 10 xx 2 + (1)/(2) (1 + 2) xx 5`
`+1 xx 10 + (1)/(2) xx 5 xx 1 = 30 m//s`
`rArr v = 30 m//s`.