An astronaut stands by the rim of a crater on the moon, where the acceleration of gravity is 1.62 m/s2. To determine the depth of the crater, she drops a rock and measures the time it takes for it to hit the bottom. If the depth of the crater is 120 m, how long does it take for the rock to fall?

12.17 secs

Explanation:

Given the following data;

acceleration due to gravity g = 1.62 m/s²

depth of the crater S = 120m

time it takes for the rock to fall t = ?

Using of the equation of motion to get the time;

S = ut+1/2 gt²

u = initial velocity of the crate = 0m/s

Substituting the given values into the equation above will give;

120 = 0 (t) + 1/2 (1.62) t²

120 = 0.81t²

Dividing both sides by 0.81

t² = 120/0.81

t² = 148.15

t = √148.15

t = 12.17secs

It will take 12.17secs for the rock to hit the bottom?