Free-Fall Practice Problems
Free-Fall Equations: 1) y  vi t  
1
2
g t 
2
2) v 2f  vi2  2 gy 3) v f  vi  g t 
4) g  9.81 m
s2
(on Earth)
Pick the appropriate free-fall equation to solve the following problems. Set up the
following problems in class by writing the givens, what we want to find, and by picking
the equation to use. Or, you can use the “vividat” method. Then, solve the problem.
For each problem you should do one or the other, (and fill in the information):
vf 
ag
Given:
Want:
Use:
or
vi 
y 
t 
1. A robot probe drops a camera off the rim of a 239 m high cliff on Mars, where the
free-fall acceleration is –3.7 m/s^2.
a. Find the time required for the camera to reach the ground.
b. Find the velocity with which it hits the ground.
2. On the moon, a feather is dropped from a height of 1.40 m. The acceleration of gravity
on the moon is -1.67 m/s2. Determine the time it takes for the feather to fall to the surface
of the moon.
3. Dionte is riding the Giant Drop at Great America. If Dionte free-falls for 2.6 seconds:
a. What will be his final velocity?
b. How far will he fall?
4. If Lebron James has a vertical leap of 1.29 m, what is his take-off speed and his hang
time (total time to move upwards to the peak and then return to the ground)?
5. The observation deck of a skyscraper is 420 m above the street. Determine the time
required for a penny to free-fall from the deck to the street below.
6. What are the differences between the free-fall equations above and the 1-D kinematics
equations we used earlier? (Hint: There are two if you compare the equations.)
7. A baseball is thrown straight up in the air with an initial velocity of 2 m/s. Draw a
picture that shows the path of the ball as it goes up and comes down. Label the initial
velocity, the velocity at max. height, and the acceleration of the ball.
Do Not Write On!