A rocket is fired vertically upwards with a net acceleration of `4 m//s^2` and initial velocity zero. After `5s` its fuel is finished and it decelerates with g. At the highest point its velocity becomes zero. Then, it accelerates downwards with acceleration g and return back to ground. Plot velocity-time and displacement -time graphs for the complete journey. Take `g=10m//s^2.`

Explanation

In the graphs, `v_(A)=at_(OA)=(4)(5)=20 m//s`.
`v_(B)=0=v_(A)-"gt"_(AB)`

`therefore t_(AB)=(v_(A))/(g)=(20)/(10)=2s therefore 70=(1)/(2)(10)`