Energy Skate Park Part 2

Friction and Thermal Energy Remember that friction is a force that opposes (works against) motion. So what does friction have to do with energy? ‪Energy Skate Park Go to the Energy Skate Park: Basics Site and go to the friction section. Click on the Bar Graph and the Grid Place the skater on the top of the ramp, and observe what happens as they move back and forth and eventually come to a stop. Use those observations to answer the following questions. Friction is transforming kinetic energy into thermal energy. What evidence is there that most of the friction occurs at the bottom of the U on the ramp? The thermal energy jumps up at the bottom The kinetic energy drops at the bottom The total energy drops at the bottom Large changes occur in both the kinetic and thermal energy at the bottom. _ explains why the total energy does not change. Newton's 2nd Law The law of conservation of energy Newton's 3rd Law The law of conservation of momentum To get this bar graph is friction turned on? Yes No Cannot Tell To get this bar graph is friction turned on? Yes No Cannot Tell To get this bar graph is friction turned on? Yes No Cannot Tell To get this bar graph is friction turned on? Yes No Cannot Tell Track Playground Click on Track Playground. Using the track pieces in the lower left-right, build a track with a single loop, like the track shown in the picture. Be sure the far left and far right of the track are higher than the top of the loop. Turn on the Bar Graph, Grid, and options and for now, set the Friction option to none.Try placing your skater at different starting points on one side of the track. Then answer the following questions. With the friction off, does the kinetic energy ever get as high as the total energy? No Yes, when the height equals zero Yes, at the top of the loop Yes, on the other side of the track at the highest point What is the minimum height you can place the skater so that he makes it all the way around the loop? It has to be at the highest point It has to be at least the same height as the top of the loop It can be as low as 1 foot beneath the loop You can place the skater anywhere. Turn the Friction on With the friction on, does the kinetic energy ever get as high as the total energy? No Yes, when the height equals zero Yes, at the top of the loop Yes, on the other side of the track at the highest point With friction on what is the minimum height, you can place the skater so that he makes it all the way around the loop? It has to be at the highest point It has to be at least the same height as the top of the loop It can be as low as 1 foot beneath the loop You can place the skater anywhere. Why did turning on the friction make such a difference to the height needed to clear the loop? You needed to have enough energy to make up for the themal energy from friction. The amount of Potential energy plus the energy lost to friction must equal the amount of potential energy at the top of the loop Both of these Create a track of your own. Sketch what it looks like in the space below. Label where on the diagram you have the greatest kinetic energy, the greatest potential energy, and two places that have the same potential energy.