An object is dropped from rest into a pit,and accelerates due to gravity at roughly 10 m/s2.It hits the ground in 5 seconds.A rock is then dropped from rest into a second pit,and hits the ground in 10 seconds.How much deeper is the second pit,compared to the first pit? Neglect air resistance.
A)four times deeper
B)two times deeper
C)three times deeper
D)five times deeper

Question

Quizplus · Accepted Answer

The depth of a pit is determined by the formula $ d = \frac{1}{2}gt^2 $. For the first pit, $ d_1 = \frac{1}{2} \times 10 \times 5^2 = 125 $ meters. For the second pit, $ d_2 = \frac{1}{2} \times 10 \times 10^2 = 500 $ meters. The second pit is $ \frac{500}{125} = 4 $ times deeper than the first pit.

An Object Is Dropped from Rest into a Pit,and Accelerates