# physics

posted by .

A bungee jumper jumps from a bridge with a 3 m long bungee cord. Once the cord starts to stretch, it acts like an ideal spring with coefficient of elasticity k=100 N/m. What should be the minimum height of the bridge in m so that this jump is safe for the jumper?

Details and assumptions
The jumper has a mass of 80 kg.
The acceleration of gravity is −9.8 m/s^2.
There are at least two ways to solve this problem.
Treat the jumper as a point mass at the end of the cord.

• physics -

potential energy decrease in fall = potential energy put into spring

m g h = (1/2) k h^2

h = 2 m g /k

• physics -

i think we will get from your way damon h be about 15.68 which is wrong..

• physics -

no no your correct but correct answer will bet putting h-3 in place of h..

• physics -

Oh, yes, sorry

• physics -

• physics -

Consider the law of conservation of energy in solving this problem.

i.e. gravitational potential energy = elastic potential energy.
So, m g (h-3) = 1/2 k x^2.

## Similar Questions

1. ### physics

A 53 kg bungee jumper jumps from a bridge. She is tied to a bungee cord whose unstretched length is 13 m, and falls a total of 35 m. Calculate the spring stiffness constant k of the bungee cord, assuming Hooke's law applies.
2. ### Physics

A 63.0-kg bungee jumper is standing on a tall platform (h0 = 45.8 m). The bungee cord has an unstrained length of L0 = 9.18 m and, when stretched, behaves like an ideal spring with a spring constant of k = 67.2 N/m. The jumper falls …
3. ### Physics

A 63.0-kg bungee jumper is standing on a tall platform (h0 = 45.8 m). The bungee cord has an unstrained length of L0 = 9.18 m and, when stretched, behaves like an ideal spring with a spring constant of k = 67.2 N/m. The jumper falls …
4. ### AP Physics B

A 63.6-kg bungee jumper is standing on a tall platform (h0 = 50.6 m). The bungee cord has an unstrained length of L0 = 9.54 m and, when stretched, behaves like an ideal spring with a spring constant of k = 67.8 N/m. The jumper falls …
5. ### physic

Bungee Jumping. A bungee jumper jumps from a tall bridge attached to a light elastic cord (bungee cord) of unstretched length L. The cord first straightens and then extends as the jumper falls. This prevents her from hitting the water! …
6. ### Physics Classical Mechanics

A bungee jumper jumps (with no initial speed) from a tall bridge attached to a light elastic cord (bungee cord) of unstretched length L. The cord first straightens and then extends as the jumper falls. This prevents her from hitting …
7. ### science

A bungee jumper jumps (with no initial speed) from a tall bridge attached to a light elastic cord (bungee cord) of unstretched length L. The cord first straightens and then extends as the jumper falls. This prevents her from hitting …
8. ### physics

A 61.0 -kg bungee jumper is standing on a tall platform (h0 = 46.0 m), as indicated in the figure. The bungee cord has an unstrained length of L0 = 9.00 m, and when stretched, behaves like an ideal spring with a spring constant of …
9. ### Physics

A 100 kg. man decides to go bungee jumping off a bridge. The bungee cord has a relaxed length of 10.0 m, and acts as a perfect spring with a stiffness constant of 80 N/m. What is the maximum distance below the bridge that he will reach?
10. ### Physics

A bungee jumper runs off a platform and falls 40m before his bungee cord begins to stretch. Once the bungee cord begins to stretch his velocity slows by 20 m/s in 12m. If the mass of the bungee jumper is 55kg, what is the average force …

More Similar Questions