(D) The gravitational force between the astronaut and the asteroid.
Reason :
All the other forces given in the options, except (D), doesn't account for the motion of the astronaut. They are the forces that act between nucleons or atoms and neither of them accounts for an objects motion.
B. truthfully it's the only one that makes sense
Answer:
13.5 m
Explanation:
M = Mass of cart = 500 kg
m = Ann's mass = 50 kg
= Velocity of Ann relative to cart = 5 m/s
= Velocity of Cart relative to Ann
As the linear momentum of the system is conserved

Time taken to reach the right end by Ann

Distance the cart will move in the 3 seconds

The negative sign indicates opposite direction
Movement of Ann will be the sum of the distances

The net movement of Ann is 13.5 m