A model rocket sits on the launch pad until its fuel is ignited, blasting the rocket upward. During the short time of blast-off, as the ignited fuel goes down, the rocket goes up because:
A) the fuel pushes on the ground.
B) air friction pushes on the escaping fuel.
C) the downward force of gravity on the rocket is less than the rate of downward momentum increase of the fuel.
D) of none of the above reasons.

Question

Quizplus · Accepted Answer

The rocket moves upward due to the conservation of momentum. As the fuel is expelled downward, the rocket gains upward momentum, and the force of gravity is less than the rate of momentum change.

A Model Rocket Sits on the Launch Pad Until Its