- #1

Junior Newton

- 9

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## Homework Statement

Hi, just wondering if you could help me with a Physics/Math assignment I'm currently working on. Involves the following questions:

New Zealand is the home of bungee jumping. One of the major jumps is located on a bridge over the Shotover River near Queenstown. In this case, the bridge is 71 m above the river. Two types of jumps are available — wet and dry. In a dry jump, the person’s fall ends just above the water surface. In a wet jump the person is submerged to a depth of 1 m. Participants jump from the bridge, fastened to an elastic rope that is adjusted to halt their descent at an appropriate level. The rope is specially designed and its spring constant is known from specifications. For the purposes of the problem, we will assume that the rope is stretched to twice its normal length by a person of mass 75 kg hanging at rest from the free end. It is necessary to adjust the length of the rope in terms of the weight of the jumper.

1. For a person of mass m kg, calculate the depth to which a person would fall if attached to a rope of the type described above, with length l metres. Treat the jumper as a particle so that the height of the person can be neglected. Discuss the assumptions made in this calculation.

2. If you were the person jumping off the 71 m attraction, find the length of rope needed for a dry jump, where the descent is halted 1 m above the water.

3. Now find the length of rope needed for a wet jump, where the descent would end 1 m below the surface of the water. Find the speed of entry to the water.

4. In practice, the bungee rope is attached to the ankles of the jumper. Refine the previous model to allow for the height of the jumper and modify the earlier calculations. Is the difference significant?

5. At present, the model does not include air resistance. Discuss the changes which would have to be made to the model to include air resistance, which is proportional to the velocity of the jumper. Discuss the difficulties involved with the mathematics of this model.

## Homework Equations

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## The Attempt at a Solution

I'm mainly stuck upon Question 5... I can calculate the velocity at any point but not sure where to find the maximum velocity to show what the major impacts of air resistance will be??[/B]