Question

I am supposed to answer these conceptual questions with this lab simulator, but I can never get the simulator to work https://phet.colorado.edu/en/simulation/legacy/energy-skate-park

Help please?

Energy State Park Lab Handout

Click on the “Energy State Park Simulation” link to perform simulations in the setup satisfying the given conditions.

Upon opening the simulation, the skate should be alternating between the walls of the skate park with no friction added and with Earth’s gravity. Click on the Show Pie Chart under the Energy Graphs section.

1. With no friction, will his motion every stop?

2. What principle can be applied to this situation?

3. What type of forces are applied here? (Conservative/Non-conservative)

4. What happens to the skater’s potential energy has he falls down a wall to the valley? What about when he moves up a wall from the valley?

5. What happens to the skater’s kinetic energy has he falls down a wall to the valley? What about when he moves up a wall from the valley?

6. Will any kinetic energy be transformed into thermal energy? If so , why? If not, why?

7. Where does the skater have the maximum potential energy?

8. Where does the skater have the maximum kinetic energy?

Now change the coefficient of friction to half way between None and Lots.

1. Are there any non-conservative forces in this simulation? If so what force?

2. With friction, will the skater ever stop?

3. Would thermal energy be created with this situation?

Conceptual Questions:

1. What is the formula for kinetic energy?

2. What is the formula for gravitational potential energy?

3. If the 75 kg skater reaches a maximum height of 5 feet, what is his maximum gravitational potential energy? (Hint: remember to convert to meters).

4. Is gravitational potential energy a conservative or non-conservative force? Is friction force a conservative or non-conservation force?

Answer 1

• With no friction the motion will not ever stop.
• The principle of conservation of energy is applied to this situation.
• The forces involved in this case is conservative force(gravity).
• The potential energy is increased when the skater moves up from valley to wall. While potential energy decreases when skater moves down the valley.
• The kinetic energy is increased when skater moves down the valley from wall. While kinetic energy decreases when skater moves up the wall from valley.
• There are no friction involved then there will not be conversion of thermal energy from kinetic energy.
• At the highest point on the wall the potential energy will be maximum.
• At the valley the kinetic energy will be maximum.
• After we change the coefficient of friction in between the none and the lots. The non conservative force involved is the frictional force.
• With the friction involved the skater will stop.
• Yes, the thermal energy will be created in this situation.
• ​​​Kinetic energy=(1/2)MV2​​​​​​
• Potential energy = Mgh. Where, g = acceleration due to gravity and h = height of wall
• Given, M = 75kg, h = 5ft = 1.5 m

Maximum potential energy = 75×9.8×1.5=1102.5 J

• Gravitation force is Conservative force.
• Friction is non-conservative force.