Author Question: A rocket moving in outer space maintains a constant acceleration (magnitude = 20 m/s2) while ... (Read 235 times)

RRMR · **on:** Jul 28, 2018

A rocket moving in outer space maintains a constant acceleration (magnitude = 20 m/s2) while ejecting fuel at a speed of 15 km/s relative to the rocket. If the initial mass of the rocket is 3 000 kg, what is the magnitude of the thrust after 800 kg of fuel have been consumed?
a. 56 kN
b. 48 kN
c. 52 kN
d. 44 kN
e. 36 kN

Question 2

A rocket with an initial mass of 1 000 kg adjusts its thrust by varying the rate at which mass is ejected. The ejection speed relative to the rocket is 40 km/s. If the acceleration of the rocket is to have a magnitude of 20 m/s2 at an instant when its mass is 80 of the original mass, at what rate is mass being ejected at that instant? Ignore any external forces on the rocket.
a. 0.40 kg/s
b. 0.50 kg/s
c. 0.60 kg/s
d. 0.70 kg/s
e. 0.80 kg/s