\f3. Play around with the mass slider control and the iction slider control. How do the RE and gravitational PE change as the mass ofthe skater changes but the 'iction remains the same\"?I 5|. How do the RE and gravitational PE change as the iction increases but the mass ofthe skater stays the sameiJ lEI. When is the gravitational potential energy the highest lowest the lowest\"? 11. When is the kinetic energy the highest the lowesJ 12. Bring the skater up to various heights on the left side ofthe track {at the top, m up, etc.]- and observe what happens when you let the skater go. Do this until you can predict the height the skater will reach on the right side ofthe track. Use the Law of Conservation ofEnergy to explain your prediction the height that the skater will reach on the right side depending on the release point on the left side. Activity 3: Build Your 011-11 Skate Park speed}. This simulation allows you to build-yohr own track in the simulator window. Select and drag the new piece oftrack to the existing track and line up the red circles for where you want them tojoin. Then, you can manipulate the track to create hills, loops, drops, m! 13. Create a track complete with hills, drops and multiple loops that your skater can complete from start to nish without getting stuck 0F. ying o' when the friction is zero. Consider the relationship between potential and kinetic energies. Include a screenshot ofyour skate park below with clearly labeled points of greatest PE and KE and least PE and KE. 14. Was your skater able to successfully complete the track 'om start to finish on your rst attempt\"?l Ifnot, indicate on the screenshot where your skater became stuck or ew off. I L\" \f19. Leave the blue slider control for the spring constant at 200 N/m. Then play around with the green slider control, which affects displacement from equilibrium. Pick five different values for the displacement and complete the table below. Trial Spring constant Displacement (m) Potential Energy (J) N/m) 1 200 2 200 200 200 5 200 20. What happens with the potential energy as the displacement changes? 21. In Excel, plot a graph of Elastic PE vs. Displacement and a graph of Elastic PE vs. (Displacement) to determine what relationship exists between the elastic PE and displacement (linear or quadratic). Include the two graphs in the space below. 22. Based on your above investigations, write down a formula for the potential energy stored in a spring as a function of the spring constant and displacement. 23. How is the elastic PE different than the gravitational PE (like the one from the skate park)? References: University of Colorado Boulder, http://phet.colorado.edu 5u-.-. ' Wear-:2- nun-q- .. . r\". \"I.\"- "l-l 1-.J'I " a; ' ' mum-n:- I ' "u ohm-3*- e. \"1'7"! 5'1- ,_I \"m ems-"- ' 1mm - u 'r no.1. lu- \"Mush,\" 1. Check all boxes in the legend {pie chart, bar graph, grid, speed). 'Watch the skater moving across the track and how the levels of PE and HE change {you can slow or pause the skater down at the bottom ofthe simulator Window to help with the ohseriation}. 1iii-"hen is the gravitational potential energy the highest the lowest? 2. When is the kinetic energy the highest the lowest:J 3. When are the kinetic and gravitational potential energy levels the same\"? 4-. Can you think of a scenario when the kinetic and gra'ritationa] potential energy could both be zero? Deserihe it below. 5. Playr around with the mass slider control. How do the kinetic and gravitational potential energies change as the mass ofthe skater ehanges'.'I 6. Bring the skater up to various heights onthe left side ofthe track [at the top= m up, etc.) and then obseri'e what happens when you let the skater go. Do this until you can predict to what height the skater will reaeh on the right side of the track. write down your prediction here: Use the Law of Conservation of Energy to explain how you ean predict the height that the skater will reach on the right side depending on where you release them on the le side: Activity 2: Skate Track with Friction Open the simulation, choose the Friction screen, and check all hoses in the legend (pie chart, bar graph grid= speed}. 1Watch the skater moving aeross the three di'erent tracks and how the lei'els ofPE and ICE change {you can slow or pause the skater down to help 1with the observation). 2