Question

A 130-kg (including all the contents) rocket has an engine that produces a constant vertical force (the thrust) of 1750 N. Inside this rocket, a 14.3-N electrical power supply rests on the floor. (a) Find the acceleration of the rocket. (b) When it has reached an altitude of 120 m, how hard does the floor push on the power supply? (Hint: Start with a free-body diagram for the power supply.)

Answer 1

a)

Force = F = 1750 N

mass = m = 130 kg

acceleration is given as

a = F/m = 1750 / 130 = 13.5 m/s²

b)

mass of power supply = m' = 14.3 /9.8 = 1.46 kg

from the free body diagram , force equation can be written as

F_n - m'g = m'a

F_n = m'(g + a)

F_n = 1.46 (9.8 + 13.5)

F_n = 34.02 N