An astronaut on a distant planet wants to determine its acceleration due to gravity. The astronaut throws a rock straight up with a velocity of +16 m/s and measures a time of 23.2 s before the rock returns to his hand. What is the acceleration (magnitude and direction) due to gravity on this planet? (Indicate direction by the sign of the acceleration.)

Answer 1

Tr = 23.2/2 = 11.6 s. = Rise time.

Vf = Vo + g*Tr = 0.
16 + g*11.6 = 0.
11.6g = -16.
g = -1.38 m/s^2.