Conservation of energy at the skate park answer key

Morgan State University Physics 101 Energy Skate Park activity 1: Introduction to Conservation of Mechanical Energy Before you begin the lab: ✓ Open the Energy Skate Park PhET simulation o https://phet.colorado.edu/sims/html/energy-skate-park-basics/latest/energy-skate-parkbasics_en.html ✓ Make sure you have Excel ✓ Grab a timer. Purpose You are investigating the relationship between kinetic energy, potential energy, and total energy when only conservative forces are present and then again when non-conservative forces are present. The data will be analyzed graphically to provide a clear trend. Directions Part 1- Conservative Forces 1. Open Energy Skate Park. Choose Intro. 2. Take time to play around with the simulation. Make sure all boxes are checked. What do you notice about the total energy, kinetic energy, and potential energy in the bar graph? What do you notice about the pie graph? What must you do to get the pie graph to be larger? -1- 3. You are measuring the changes in energy- total, kinetic, and potential over time. To do this, we need to define our system. This is a skater-earth system. 4. We also need to establish numbers for mass and speed. 10-m/s 8-m/s 12-m/s 6-m/s 14-m/s 4-m/s 16-m/s 18-m/s 2-m/s 5-kg 15-kg 20-m/s 0-m/s 10-kg 5. Place the 10-kg skater at 6-m and start the timer when you hit play. Pause both timer and sim when the skater is at 4-m, 2-m, 0-m, and 6-m. Record the height, speed, and time in the table below. Continue recording until you’ve reached 45-s. Time 0-s Height 6-m -2- Velocity 0-m/s 6. Calculate the potential energy, kinetic energy, and total energy of the system using the data from #4. Time (x-axis) Potential Energy (y-axis) Kinetic Energy (y-axis) Total Energy (y-axis) 7. Graph the three data sets in #5 using Excel. Do not forget the title. Part 2- Non-conservative Forces 8. Click “Friction” at the bottom of the simulation. 9. Take time to play around with this simulation. Make sure ALL boxes are checked. -3- What do you notice about the total energy, kinetic energy, and potential energy in the bar graph? What do you notice about the final thermal energy & the total energy once the skater has stopped? 10. You are measuring the changes in energy- total, kinetic, and potential over time. To do this, we need to establish numbers for mass and speed as well as our system: This is a skater-earth system. 10-m/s 8-m/s 12-m/s 6-m/s 14-m/s 4-m/s 16-m/s 18-m/s 2-m/s 5-kg 15-kg 20-m/s 0-m/s 10-kg 11. Place the 10-kg skater at 6-m and start the timer when you hit play. Pause both timer and sim when the skater is at 4-m, 2-m, 0-m, and 6-m. Record the height, speed, and time in the table below. Continue recording until you’ve reached 45-s. Time Height Velocity 0-s 6-m 0-m/s -4- 12. Calculate the potential energy, kinetic energy, and total energy of the system using the data from #10. Time (x-axis) Potential Energy (y-axis) Kinetic Energy (y-axis) -5- Thermal Energy (y-axis) Total Energy (y-axis) 13. Graph the four data sets in #11 using Excel. Follow the same procedure as before. Make the thermal energy a linear fit. 14. You are now finished with the experiment itself. Now type a formal lab to this assignment. Part c – create your own track 1. Explain how you could use your investigation to plan a track that is fun, challenging and one that is relatively safe. You might think for example: When does he: fly off an end? make it to the top a hill? or land a jump? 2. Build a good track and sketch it. Then use the Energy Graphs to study the Skater’s energy. • Decide which graphs or chart best helps you understand what makes your track successful • Look in your text to find out what the Conservation of Mechanical Energy means and explain it in your own words. • Explain why your track is successful in terms of Conservation of Mechanical Energy.