PhET Energy Skate Park Lab-Part II

What is your last name?

18. Using the grid, what is the height of the top of the loop?

19. What is the minimum height you can place the skater so that they make it all the way around the loop?

20. Explain, in terms of energy, why the skater must be released from at least the height in #18 to make it through the loop.

21. With the friction off, does the kinetic energy ever get as high as the total energy? If so, when? If not, why not?

22. With the friction on, does the kinetic energy ever get as high as the total energy? If so, when? If not, why not?

23. What kind of work does friction do on the skater: negative or positive? Explain your answer using the work-kinetic energy theorem.

24. Now with the friction on, distort the loop until the skater makes it all the way around the loop. What did you have to change? Is this different than when friction was off? Why?

25. In questions 22-24, we might say the skater “lost” or “dissipated” some mechanical energy. Where is this energy going according to your bar graph? What does this mean in real life?

26. Now what is the minimum height you can place the skater so that they make it all the way around the loop the first time? Speculate on why this might be true.