# 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

Loose Gravitate on Different Worlds Objects in loose gravitate on the globe entertain acceleration ay=−9.8m/s2 . On the moon, loose gravitate acceleration is almost 1/6 of the acceleration on globe. This changes the flake of problems involving loose gravitate. Control persuasion, divine you spring direct upward, leaving the reason with rapidity vi and then steadily slacking until reaching cipher rapidity at your leading subject-matter. Besuit your moderate rapidity is steadfast chiefly by the power of your leg muscles, we can postulate your moderate rapidity would be the corresponding on the moon. But regarding the equation h=v22g we can discern that, with a smaller loose-gravitate acceleration, your completion acme would be superior. The subjoined questions entreat you to reckon environing how sure brawny feats potentiality be performed in this reduced-gravity environment.

Part A

If an astronaut can spring direct up to a acme of 0.7 m on globe, how noble could he spring on the moon?

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

Part B

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

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

On the globe, an astronaut throws a globe direct upward; it stays in the essence control a whole occasion of 2.8 s anteriorly reaching the reason anew. If a globe were to be thrown upward with the corresponding moderate despatch on the moon, how fur occasion would ignoring anteriorly it mistake the reason?

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