Question 5

A 12 kg weather rocket generates a thrust of 200 N. The rocket, pointing upward, is clamped to the top of a vertical spring. The bottom of the spring, whose spring constant is 550 N/m, is anchored to the ground. Initially, before the engine is ignited, the rocket sits at rest on top of the spring. The spring is compressed by 20 cm.

After the engine is ignited, what is the rocket’s speed when the spring has stretched 40 cm?

Assume no air drag.