Question

The acceleration of gravity on the moon is about 1.6 m/sec 2. An experiment to test gravity compares the time it takes objects to reach a speed of 10 m/sec after being dropped from rest. How long does an object dropped on the moon have to fall to reach this speed compared to an object dropped on Earth?
Select one:
a. 1.6 times as long
b. 6.1 times as long
c. 9.8 times as long
d. 15.7 times as long

Answer 1

The answer is b. 6.1 times as long

Step 1: Calculate the time it takes objects to reach a speed on the Moon.
Step 2: Calculate the time it takes objects to reach a speed on the Earth.
Step 3. Divide the time on the Moon by the time on the Earth.

Use the formula: v2 = v1 + at
v2 - the final velocity
v1 - the initial velocity
a - gravitational acceleration
t - time

Step 1.
Moon:
v1 = 0 (because it is free fall)
v2 = 10 m/s
a = 1.6 m/s²
t = ?
______
v2 = v1 + at
10 = 0 + 1.6t
10 = 1.6t
t = 10/1.6
t = 6.25 s


Step 2.
Earth:
v1 = 0 (because it is free fall)
v2 = 10 m/s
a = 9.81 m/s²
t = ?
______
v2 = v1 + at
10 = 0 + 9.81t
10 = 9.81t
t = 10/9.81
t = 1.02 s


Step 3:
6.25 s / 1.02 s = 6.1 s