Name: _____________________________________
Projectile Motion
OBJECTIVE: To study and apply the equations for two-dimensional motion with constant
acceleration.
MATERIALS:
• A tennis ball
• A stop-watch or your smart phone
• Measuring tape
PROCEDURE:
First watch the videos at D2L → Content → Labs → Projectile Motion
If you want to perform the experiment yourself, toss a tennis ball upward and forward. Take
care to notice the point of release (initial height and initial position on the ground). As you
release the ball, you will need help from someone to start the timer. The timer should be
stopped as the ball contacts the ground. Make sure that the ground where the ball is thrown
and where the ball lands are at the same elevation. Mark the spot where the ball lands and
measure the distance from the point of release to the landing location. It is recommended that
your helper waits for the ball close to its expected landing point so that he/she can mark it
more accurately.
Repeat this procedure until you have 4 sets of data and fill the table below with your data.
Given only the release height, the time in air, and the horizontal distance traveled, you will be
able to find detailed information on the flight of the ball using the equations for projectile
motion.
Experiment
#
Release height (m)
(initial height)
Time in air (s)
(from release to
landing)
Horizontal distance
traveled (m)
1
2
3
4
1
Those who do not have anyone to help out with the experiment can use data generated by the
professor and continue with the analysis.
Experiment
#
Release height (m)
(initial height)
Time in air (s)
(from release to
landing)
Horizontal distance
traveled (m)
1
1.68 m
0.80 s
2.9 m
2
1.75 m
0.92 s
3.3 m
3
1.61 m
0.91 s
3.45 m
4
1.51 m
0.75 s
2.7 m
CALCULATION & QUESTIONS:
1. What is the value for the horizontal acceleration vector (direction and magnitude)?
2. What is the value for the vertical acceleration vector (direction and magnitude)?
3. In class, we have studied projectile motion, which is a special case of motion under
constant acceleration. Below, give the equations for the displacement and velocity as
functions of time for both horizontal and vertical motion.
Equation for horizontal position: ______________________________________________
Equation for horizontal velocity: ______________________________________________
Equation for vertical position: ________________________________________________
Equation for vertical velocity: ________________________________________________
4. We also discussed an equation that will allow computation of velocity as a function of
position in the vertical direction. Write that equation below.
Equation for vertical velocity as a function of position: _____________________________
2
Using equations above, complete the following table with values for initial horizontal velocity,
final horizontal velocity, initial vertical velocity, final vertical velocity, and maximum height
traveled by the ball (initial means just as the ball leaves the thrower’s hand; final means just
before the ball hits the ground). Assume no air resistance.
Experiment
#
Initial
Horizontal
Speed (m/s)
Final
Horizontal
Speed (m/s)
Initial
Vertical
Speed (m/s)
Final
Vertical
Speed (m/s)
Maximum
Height of
Travel (m)
1
2
3
4
Show your calculations with proper equations, values and units for each experiment.
CALCULATIONS:
3
Using these values, draw the projectile trajectory of the tennis ball from your Experiment #4
(similar to the ones shown in class and in your textbook). Using the values from Experiment
#4, draw vectors (with magnitudes and directions clearly defined with angles) and label the
following:
•
•
•
•
Initial total velocity
Velocity at the maximum height
Final total velocity
Maximum height
Note: The initial vertical height will be your release height.
Projectile
Motion of the
Tennis Ball
Show your calculations below for initial total velocity and final total velocity with direction
and magnitudes. (Do not forget to include the angles to define direction).
4