Consider a vehicle with the velocity-time graph on the left.

a) FInd the velocity at 6s
40m/s

b) Find its acceleration during the first 4 seconds.
acc =change in velocity/time = 20/4 =5m/s/s

c) How far did the vehicle travel during the first 7 seconds.
Distance is given by the area under the graph between 1 and 7 seconds. In this case it is 100m

d) When did the vehicle start its journey back?

10 seconds into the journey the vehicle started its way back.

The image on the left shows the velocity time graph of a rocket that is launched vertically skywards.

a) What is the altitude reached by the rocket 3 seconds into the flight?
75m

b) What is the acceleration of the rocket during the 3 - 6 second time period?
3.3m/s/s

c) What is the altitude of the rocket 7 seconds into the flight?
Distance is given by the area under the graph between 0 and 7 seconds.
270m

d) At what time did the engines of the rocket cease stop producing thrust?

Just after the 6 second mark the engines stopped producing thrust.