UC Mechanical Energy & Gravitational Potential Energy Lab Report
Energy Skate Park PhET LabDue: 11:59pm on Sunday, June 13, 2021
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PhET Tutorial: Energy Skate Park: Basics
To understand conservation of mechanical energy involving gravitational potential energy and kinetic energy.
For this problem, use the PhET simulation Energy Skate Park: Basics. This simulation allows you to explore the motion and energetics of a skater riding along a
Start the simulation. When you click the simulation link, a new window will load. Click on Intro to get started.
You can click and drag the skater to any location and release the skater from rest.Watch the skater skate up and down the track.
Click on Bar Graph to see the relative magnitudes of the kinetic, potential, thermal, and total energies as a function of the skater’s position. Try Pie Chart to
see the same information as a pie chart.
Play around with the simulation. When you are done, click on the Reset button before answering the questions.
Click on Bar Graph, and observe the kinetic energy bar as the skater goes back and forth. You can select Slow Motion below the track for a more accurate
Where on the track is the skater’s kinetic energy the greatest?
You did not open hints for this part.
the same everywhere.
The skater’s kinetic energy is
at its maximum value at the locations where the skater turns and goes back in the opposite direction.
at its maximum value at the lowest point of the track.
Part B Complete previous part(s)
Part C Complete previous part(s)
Ignoring friction, the total energy of the skater is conserved. This means that the kinetic plus potential energy at one location, say E1 = K1 + U1 , must be
equal to the kinetic plus potential energy at a different location, say E2 = K2 + U2 . This is the principle of conservation of energy and can be expressed
as E1 = E2 . Since the energy is conserved, the change in the kinetic energy is equal to the negative of the change in the potential energy:
K2 − K1 = −(U2 − U1 ), or ∆K1 = −∆U2 .
At the bottom of the simulation window, click on Playground. For this part of the tutorial, you should have the Friction slider (in the upper right part of the
window) set to “None,” which means no thermal energy is generated. Select the Show Grid option. Then, add a track by clicking and dragging on a new
track (the shape with three circles in the bottom left of the window) and placing it near the skater. You can then click and drag on individual circles to
stretch and /or bend the track and make it look as shown below. The bottom of the track should be 1 m above the ground, and both ends of the track
should be at a height of 7 m
Place the skater on the track 7 m above the ground, and look at the resulting motion and the Bar Graph showing the energetics.
Match the approximate numerical values on the left with the energy type categories on the right to complete the equations. Assume that the mass of the
skater is 75.0 kg and that the acceleration of gravity is 9.8 N/kg .
Match the values in the left column to the appropriate blanks in the sentences on the right. Values can be used once, more than once, or not at
1. Total energy at initial position =
2. Potential energy at initial position =
3. Kinetic energy at initial position =
4. Total energy at bottom of track =
5. Potential energy at bottom of track =
6. Kinetic energy at bottom of track =
Part E Complete previous part(s)
Part F Complete previous part(s)
Part G Complete previous part(s)
Part H Complete previous part(s)
Part I Complete previous part(s)
PhET Interactive Simulations
University of Colorado
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