For a particle moving in a straight line, the position-time graph is as shown in the figure. Find the velocity of the particle at time `t=1 s` and `t=4 s`. Also sketch the v-t graph.

Explanation

`OA: t=0` to `t=2 s`
Slope`=tan alpha=8/2=4`
Velocity`=4 m//s`

`AB: t=2` to `6 s`
Slope`=-tanbeta=-8/4=-2`
Velocity `=-2 m//s `
For v-t graph:
`t=0` to `t=2 s, v=4 m//s`
`t=2` to `6 s, v=-2 m//s`