Answer:
The free body diagram of John is shown in the attached figure (in the FBD john's mass is supposed to be concentrated at his center of mass and FBD is made of center of mass)
b) As shown in the FBD the ground reaction forces are:
i) In X direction 
ii) In Y direction 
c) The respective accelerations in x and y direction's is calculated by newton's second law as indicated under

A. An indirect measure of heat energy
They had to use thrust because there is no air on the moon meaning that parachutes would be totally useless because parachutes require air to create drag. Fun fact since there is no air on the lunar surface sound waves cannot be made since there are no air molecules for the waves to pass through, so that's why they use radio's in space.
Um use quizlet so that u can get the answer