A particle is projected upwards with velocity `40 m//s.` Taking the value of `g=10 m//s^2` and upward direction as positive, plot a-t,v-t and s-t graphs of the particle from the starting point till it further strikes the ground.

Explanation

The particle reaches the highest point after time t.
`0=40-g timpliest=4 s`
The particle returns to the point of projection at time `t=8s`.
v-t graph: `t=0, v=40 m//s`
`t=4 s, v=0`
`t=8 s, v=-40 m//s`
`v=u-g t=40-10 t`
Shape: `y=40-10x`(straght line)
`y=c+mx`
`c=40`, +ve
`m=-10`, -ve

s-t graph: Maximum height attained by the particle
`0=(40)^(2)-2gh=1600-2xx10xxh`
`implies h=80 m`
`t=0, s=0`
`t=4 s, s=80 m`
`t=8 s, s=0`
`s=ut-1/2 g t^(2)`
`s=40 t-5t^(2)`
Shape: `y=40x-5x^(2)` (parabola)
Since the coefficient of `x^(2)` is -ve, the parabola is open downward.

a-t graph: `a=-g=-10 m//s^(2)`
Shape: `y=-10` (straight line, parallel to the x-axis, below the origin)

Note: Upward direction is assumed positive.