UTF-8
SAM E1 Model 1
255255192
The Energy of a Skateboarder
The Energy Skate Park uses Newton's Laws to predict the motion of a skateboarder. You can make a skateboard track of any shape. The shape of the track is proportional to the potential energy of the skateboarder. This is a fun way to create a track that looks like the Lennard-Jones potential. Go to the Energy Skate Park and explore how potental energy and kinetic energy are related.
The Energy Skate Park opens in a separate window. Once it is open do this:
Play around with it to get a "feel" for how it works.
Click on the "Energy vs. Position" button to see the energy graph. Play around with the buttons in the lower left to get the right scale.
Check the "Potential Energy Reference" checkbox and move the dotted line up.
Move the track around, add some new track, and try to make a track that looks like the picture below.
Shape the track so that the skateboarder stays on the track.
Be sure the skater goes very slowly on the left side.
You should be able to get graphs that look like those below.
Look carefully at the slope of the track and how that influences the force on the skateboarder.
Use the Energy Skate Park to answer the following questions:
We now return to the atomic scale and look at energies there.
<Previous><Index><Next>
1
true16
1
true16
http://phet.colorado.edu/simulations/energyconservation/energyconservation.jnlp
20.0
org.concord.modeler.text.BulletIcon$SquareBulletIcon
20.0
org.concord.modeler.text.BulletIcon$SquareBulletIcon
20.0
org.concord.modeler.text.BulletIcon$SquareBulletIcon
20.0
org.concord.modeler.text.BulletIcon$SquareBulletIcon
20.0
org.concord.modeler.text.BulletIcon$SquareBulletIcon
20.0
org.concord.modeler.text.BulletIcon$SquareBulletIcon
20.0
org.concord.modeler.text.BulletIcon$SquareBulletIcon
20.0
org.concord.modeler.text.BulletIcon$SquareBulletIcon
1
40.0
Skate Park LJ potential.png
org.concord.modeler.PageTextArea
500
120
<html>
What is the direction and size (large, medium, small) of the forces at the seven blue dots on the picture above? Where is the force least and greatest?
</html>
Going left to right: For 1-3 the force is to the right; for 4-7 the force is to the left. The force is smallest at 1, moderate at 2 and 3, and larger going from 4-7. The greatest force is at number 7.
org.concord.modeler.PageTextArea
500
100
<html>
Does the KE always mirror the PE? Why?
</html>
As PE drops, there is a force causing the skater to speed up, increasing KE. As PE rises, the force is against the direction, slowing down the skater. These increases and decreases always balance.
org.concord.modeler.PageTextArea
500
100
<html>
What does a flat total energy graph tell you?
</html>
org.concord.modeler.PageTextArea
500
120
<html>
Change the location of the zero of potential energy. What changes in the energy graphs when the zero of potential is changed?
</html>
It moves the PE graph up and down without changing its shape.
1
true
page4.cmltrue
true
index.cmltrue
true
page6.cmltrue
true