Download Energy of a Ball Lab

Energy of a Ball Lab
Purpose: To see that the total energy of a tossed ball is constant.
PreLab
1. Sketch the following graphs for a ball tossed into the air.
potential energy graph
kinetic energy graph.
total energy graph.
Get signed by instructor. _________
MATERIALS
Computer
LabPro
Logger Pro
Vernier Motion Detector
Ball
PROCEDURE
1. Set up computer and labpro equipment with motion detector. Open Physics with Computers: Energy
of a Ball Toss Experiment 16.
2. Use the balance to measure the mass of the ball. Mass of ball = ________kg make sure it’s in kg!
3. Place the motion detector on the ground.
4. Collect data for one clear ball toss.
5. Use the button on the tool bar to get then record the height and velocity. Be sure to collect data when
the ball is in the air NOT in your hand.
6. Calculate the energy.
Height
Velocity
Potential
Energy
Kinetic
Energy
Total
Energy
Way Up
Top
Way Down
Is the total energy constant? If not recollect data!
Analysis
To make graphs on the computer of PE and KE we need to enter the mass of the object.
Enter the mass of the ball in the bottom right corner.
Physics with Computers
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Make a new graph. Click on the y-axis label of the velocity. Uncheck the velocity column and check the
kinetic energy and potential energy columns. Click
to draw the new plot. Double click on the
background of the graph check to auto scale the graph. COPY THIS GRAPH TO A WORD DOCUMENT!
Questions
1. The potential and kinetic energy should
[peak at the same time / peak at the opposite times / be completely unrelated]
2. If mechanical energy is conserved in this system, the sum of the kinetic and potential energies should
[ be equal to one / vary as the ball moves / be a constant value].
3. Check your prediction; make a new graph. Click on the y-axis label of the energy check the total energy
column (you may have to scroll down) in addition to the other energy columns. Click
to draw the
new plot. Your graph should look like this:
4. COPY THE TOTAL ENERGY GRAPH TO A WORD DOCUMENT.
5. From the shape of the total energy vs. time plot, you can conclude that the total mechanical energy in the
mass and spring system will [ be equal to one / vary as the ball moves / be a constant value].
On the same document as your energy graphs, discuss the following ideas:

where the ball has its highest and lowest speed,

where it has the highest and lowest kinetic energy,

where the ball has the highest and lowest gravitational potential energy.
On the total energy graph above identify the place where the ball has

no energy,

positive work,

constant energy that is conserved,

negative work,

no energy.
Physics with Computers
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