Question

As a rocket is fired from a launch pad, its speed and acceleration increase with time as its engines continue to operate. Explain why this occurs even though the thrust of the engines remains constant.

Answer 1

The engine is burning fuel (part of the rockets mass) and so as it continues its journey the mass of the rocket is becoming less and less. As Force = mass x acceleration then acceleration = Force / mass So if the force is constant, we can see from the equation that if the mass gets smaller, the acceleration must get bigger.