A ball is tossed straight up from the surface of a small spherical asteroid with no atmosphere. The ball goes to a height ewual to the asteroid's radius and then falls straight down towardd the surface of the asteroid. What forces if any act on the ball while it is on the way up?

a) only a decreasing gravitational forces acts downward
b) Only an increasing gravitational gorce that acts downwards.
c) only a constant gravitational gorce that acts downwards
d) Both a constant gravitational foce that acts downwards and a decreasing force that acts upwards.
e) No foces act on the ball

With there being no atmosphere would g be contant thus the answer is c) or is the answer d)?

g is NOT constant, either there or on Earth. g depends on the inverse distance squared from the center. As one gets more altitude, g decreases. In any case, the force is "downward", or attractive.

1 answer

a. Only decreasing gravitational force acts on the ball.