1. MegaZip at Sentosa Sep 2011

7. Questions 1.Describe the energy changes as a person moves down along the flying fox. 2.Using the law of conservation of energy, estimate the vertical height h down the flying fox needed for him to reach a speed of 50 km/h, starting from rest at the tower.

8. Questions 3. Estimate the distance d moved along the cable of the flying fox just before he reached 50 km/h, assuming the cable is at an angle of 10 degrees to the horizontal. 4. State any other assumption(s) you have made in the above calculations.

9. Questions 5. Draw and label a free body diagram of person A (with harness) if he is hanging at rest. A A

10. Questions 6. Draw and label a free body diagram for the point of suspension B (hook that harness is attached to) which is moving along the cable. 7. Suggest what type of mechanism might be used to slow down the person before the landing point. B B

11. Suggested answers 1. Describe the energy changes as a person moves down along the flying fox. His gravitational potential energy decreases and is converted to kinetic energy.

12. Suggested answers 2. Using the law of conservation of energy, estimate the vertical height down the flying fox needed for him to reach a speed of 50 km/h starting from rest at the tower. v = 50 km/h = 50 x 1000 / 3600 = 13.89 m/s Loss in g.p.e. = Gain in k.e. mgh = 1/2 mv^2 h = v^2 / 2g= (13.89^2) / (2 x 10) h = 9.647 = 9.65 m

13. Suggested answers 3. Estimate the distance d moved along the cable of the flying fox just before he reached 50 km/h, assuming the cable is at an angle of 10 degrees to the horizontal. Consider right-angle triangle. sin 10 = opposite / hypothenuse = 9.647 / d d = 9.647 / cos 10 = 55.55= 55.6 m

14. Suggested answers 4. State any other assumption(s) you have made in the above calculations. Neglect air resistance and friction along the cable of the flying fox.

15. Suggested answers 5. Draw and label a free body diagram of person A (with harness) if he is hanging at rest. A A weight tension

16. 6. Draw and label a free body diagram for the point of suspension B (hook that harness is attached to) which is moving along the cable. B B friction normal contact force tension

17. Suggested answers 7. Suggest what type of mechanism might be used to slow down the person before the landing point. There could be an elastic rope that hooks onto the person’s harness hook and stretches in the opposite direction. There could be a cushion onto which the harness hook collides and slow down.

18. Forest Adventure, Bedok Reservoir