An astronaut, whose mission is to go where no one has gone before, lands on a spherical planet in a distant galaxy.
as she stands on the surface of the planet, she releases a small rock from rest and finds that it takes the rock 0.420 s to fall 1.90 m.
a) if the radius of the planet is 7.40×107 m,
b) what is the mass of the planet?

Explanation:

As we know that the that the Astronaut dropped a stone on the surface of the planet takes 0.420 s to fall a distance of d = 1.90 m

so we will have

now we know that the acceleration due to gravity is given as

so we will have

(75°f − 32) × 5/9 = 23.889°c

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s