Chapter 8, Problem 39A

Would it be a dangerous mistake for a bungee jumper to use a steel cable rather than an elastic cord?

To determine

Whether it would be dangerous mistake for a bungee jumper to use a steel cable rather than an elastic cord.

Answer to Problem 39A

Yes

Explanation of Solution

Introduction:

Impulse on an object is given by,

  $F\Delta t=\Delta p$

Where,

  $F=$ force exerted on an object

  $\Delta t=$ time taken to change its momentum

  $\Delta p=$ change in momentum of the object

Now, if a steel cable would be used then in case of fall of bungee jumper, there would be no stretch in the cable. Due to this, for sudden change in momentum, the impact force on the cable would be more. However, if the elastic cord would be used in place of the elastic cord, then there will be stretch in the cord for the assumed case which will increase the impact time. Hence, for the same change in momentum, the impact force will be less.

Conclusion:

Hence, it is dangerous to use steel cables at the place of the elastic cords in bungee jumping.