Alunar lander in powered descent at 100 m above the surface of the moon slows down from a velocity of 20 m/s to 0.5 m/s at constant acceleration. assume that the lander has a mass of 20,000 kg and that burning the fuel does not change the mass. answer the following questions: how do i calculate  the thrust? , all i need is to know what kind of equations i use for the question. i can do the rest.