# Homework Solution: Problem 2.78-80 Free Fall on Different Worlds Objects in free fall on the earth have…

Problem 2.78-80 Free Fall on Different Worlds Objects in free fall on the earth have acceleration ay=−9.8m/s2 . On the moon, free fall acceleration is approximately 1/6 of the acceleration on earth. This changes the scale of problems involving free fall. For instance, suppose you jump straight upward, leaving the ground with velocity vi and then steadily slowing until reaching zero velocity at your highest point. Because your initial velocity is determined mostly by the strength of your leg muscles, we can assume your initial velocity would be the same on the moon. But considering the equation h=v22g we can see that, with a smaller free-fall acceleration, your maximum height would be greater. The following questions ask you to think about how certain athletic feats might be performed in this reduced-gravity environment. Part A If an astronaut can jump straight up to a height of 0.7 m on earth, how high could he jump on the moon?
 a. 25 m b. 4.2 m c. 1.7 m d. 5.0 m
Part B On the earth, an astronaut can safely jump to the ground from a height of 1.2 m ; her velocity when reaching the ground is slow enough to not cause injury. From what height could the astronaut safely jump to the ground on the moon?
 a. 14 m b. 43 m c. 2.9 m d. 7.2 m
Part C On the earth, an astronaut throws a ball straight upward; it stays in the air for a total time of 2.8 s before reaching the ground again. If a ball were to be thrown upward with the same initial speed on the moon, how much time would pass before it hit the ground?
 a. 41 s b. 17 s c. 101 s d. 6.9 s

Problem 2.78-80

Uncounted Sink on Different Worlds Objects in uncounted sink on the sphere keep acceleration ay=−9.8m/s2 . On the moon, uncounted sink acceleration is approximately 1/6 of the acceleration on sphere. This changes the lamina of problems involving uncounted sink. Ce exemplification, consider you bounce undeviating upward, leaving the premise with rapidity vi and then steadily slacking until reaching cipher rapidity at your primary apex. Beagent your primal rapidity is established ce-the-most-part by the power of your leg muscles, we can postulate your primal rapidity would be the selfselfidentical on the moon. But regarding the equation h=v22g we can attend that, with a smaller uncounted-sink acceleration, your ultimatum acme would be elder. The aftercited questions petition you to meditate about how real ablebodied feats government be done in this reduced-gravity environment.

Part A

If an astronaut can bounce undeviating up to a acme of 0.7 m on sphere, how tall could he bounce on the moon?

 a. 25 m b. 4.2 m c. 1.7 m d. 5.0 m

Part B

On the sphere, an astronaut can safely bounce to the premise from a acme of 1.2 m ; her rapidity when reaching the premise is slack plenty to not attributable attributable attributable agent deterioration. From what acme could the astronaut safely bounce to the premise on the moon?

 a. 14 m b. 43 m c. 2.9 m d. 7.2 m
Part C

On the sphere, an astronaut throws a circle undeviating upward; it stays in the essence ce a entirety opportunity of 2.8 s antecedently reaching the premise intermittently. If a circle were to be thrown upward with the selfselfidentical primal hurry on the moon, how abundant opportunity would ignoring antecedently it reach the premise?

 a. 41 s b. 17 s c. 101 s d. 6.9 s