Question

Ignoring friction, the total energy of the skater is conserved. This means that the kinetic plus potential energy at one location, say E1=K1+U1, must be equal to the kinetic plus potential energy at a different location, say E2=K2+U2. This is the principle of conservation of energy and can be expressed as E1=E2. Since the energy is conserved, the change in the kinetic energy is equal to the negative of the change in the potential energy: K2❝K1=❝(U2❝U1), or ΝK1=❝ΝU2.

Select the Show Grid option. Then, pull the bottom of the track down such that it is 1 m above the ground (click and drag on the blue circle on the bottom of the track). Confirm that the mass of the skater is set to 75.0 kg (select Choose Skater to view mass) and that the acceleration of gravity is set at 9.81 N/kg .

Clear all plots, place the skater on the track 7 m above the ground, and look at the resulting motion and the graph showing the energetics.

Match the approximate numerical values on the left with the energy type categories on the right to complete the equations.

1) Total energy at initial position =

2) Potential energy at initial position =

3) Kinetic energy at initial position =

4) Total energy at the bottom of the track =

5) Potential energy at the bottom of the track =

6) kinetic energy at the bottom of the track =

option answers:

5145J

735J

0J

4410J

Answer 1

1. 5145J

2. 5145J

3. 0J

4. 5145J

5. 735J

6. 4410 J

Answer 2

1) 5145 J

2) 5145 J

3) 0 J

4) 5145 J

5) 735 J

1) 4410 J