1. The formula for potential energy is PE = mgh.
2. For the first diagram: mass = 2 kg, height = 3 m, g = 9.8 m/s² → PE = 2 × 9.8 × 3 = 58.8 J.
3. For the second diagram: mass = 20 kg, height = 3 m, g = 9.8 m/s² → PE = 20 × 9.8 × 3 = 588 J.
4. For the third diagram: mass = 2 kg, height = 6 m, g = 9.8 m/s² → PE = 2 × 9.8 × 6 = 117.6 J.
5. Comparing the three: the second object (20 kg at 3 m) has the greatest potential energy (588 J), followed by the third (2 kg at 6 m, 117.6 J), then the first (2 kg at 3 m, 58.8 J).
6. Potential energy increases with greater mass or greater height.
7. Kinetic energy depends on mass and velocity, given by KE = ½mv².
8. For the first kinetic energy diagram: mass = 10 kg, velocity = 2 m/s → KE = ½ × 10 × 2² = 20 J.
9. For the second diagram: mass = 10 kg, velocity = 4 m/s → KE = ½ × 10 × 4² = 80 J.
10. For the third diagram: mass = 2 kg, velocity = 4 m/s → KE = ½ × 2 × 4² = 16 J.
11. Comparing the three: the second object (10 kg at 4 m/s) has the greatest kinetic energy (80 J), followed by the first (10 kg at 2 m/s, 20 J), then the third (2 kg at 4 m/s, 16 J).
12. Kinetic energy increases with greater mass or greater velocity, and velocity has a squared effect.
13. In the roller coaster example, at point A (highest point), potential energy is maximum and kinetic energy is minimum; at point B (lowest point), potential energy is minimum and kinetic energy is maximum.
14. Energy transforms between potential and kinetic forms but total mechanical energy remains constant if friction is ignored.
15. At point C, halfway down, potential energy is half of that at A, and kinetic energy is equal to the loss in potential energy from A to C.
16. The law of conservation of energy states that energy cannot be created or destroyed, only transformed or transferred.
Parent Tip: Review the logic above to help your child master the concept of potential and kinetic energy worksheet high school.
