A weather rocket is launched straight up. Seconds into the flight, its velocity is 130m/s and it is accelerating at 19 m/s^2. At this instant, the rocket's mass is 59 kg and it is losing mass at the rate of 0.55 kg/s. What is the net force on the rocket?
1049,5 N up
Rocket's motion depends on Newton 2 and Newton 3.
At time t, rocket has mass m, moves with velocity
Therefore momentum at time t is
Momentum at time t + dt is
Therefore change in momentum is
This is known as the Rocket Equation and may be used to solve this problem.
Substituting in we get