Consider the velocity-time graph of a model rocket travelling vertically skyward. At what point does the rocket run out of fuel?
A) A B) B C) C D) D E) The rocket never runs out of fuel.

The Solution...

When the rocket runs out of fuel it will start to slow down as it ascends skyward. Since it is still travelling in the upward direction the velocity will start to decrease but remain in the positive region of the graph. As the rocket approaches apogee its velocity will tend to zero as it transitions from a positive to a negative velocity.

So fuel runs out at point A

(c) Dynamic Science.