The acceleration time graph of a particle moving along a straight line is as shown in figure. At what time (in second) the particle acquire its initial velocity?

Explanation

`a=a_(0)t+a_(1)`,0,a=`a_(1)`=10,a=0 at t=4 seconds.
0=+4`a_(0)`+10,`a_(0)`=-2.5
a=2.5 t+10,`(dv)/(dt)`=-2.5t+10
`int`dv=`int`(-2.5t+10)dt, v=`-2.5(t^(2))/(2)`+10t+c
t=0,C=`v_(0), v=-2.5(t^(2))/(2)+10t+v_(0)`
`v=v_(0)-2.5(t^(2))/(2)+10t=0,2.5(t^(2))/(2)=10t`
t=8 seconds