Video Analysis – “Cart Rolling Down Ramp”
Review:
To review Hooke’s law, have students go to:
Click the green “Run Now” button in the lower right corner of the image.
Student Directions:
When the simulation starts, have students explore the simulation for the first 10 minutes.
“Pick up” one of the 4 known masses and hang it on the bottom of spring one. Use conservation of energy equations to calculate the spring constant of the first spring.
K spring 1 =______
What happens to the length of the spring when you decrease the “softness” of the spring? (Note: spring 3 is the spring that will change).
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What do you think happens to the spring constant? ______
Explain your thoughts:
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Next step:
Open up the energy skate park simulation:
Click the green “Run Now” button in the lower right corner of the image.
Directions:
Spend about 10 minutes exploring this simulation. Make sure to select the “bar graph” button to observe the change in energy types as the skater moves.
How does the kinetic energy and potential energy compare?
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If I were to go out to the skate park and show my moves on the half pipe, there would be some friction involved. Scroll down on the simulation page and add some friction. While keeping your bar graph up, how does it change when you add friction to the mix?
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After reviewing the simulations, watch the following video of a cart rolling down the ramp into the spring and take direct measurements to solve for the spring constant.
Develop a method for calculating the spring constant using the video above.
What values will you need to measure?
In terms of energy, what values will be set equal (i.e. what will your equation look like to solve for k)?
What is the spring constant of the spring used at the end of the ramp?
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Calculate the initial amount of energy the cart started with.
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Did the cart rebound to the same position as it started at? If not, where did it end up?
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Calculate the difference in initial gravitational potential energy before the cart was released and the final gravitational potential after the rebound.
If your answers differ, why? (Hint: think about where the energy went to)