Question

using Sig-figs pls.

1. A 55-kg female bungee jumper fastens one end of the cord (made of elastic material) to her ankle and the other end to a bridge. Then she jumps off the bridge. As the cord is stretching, it exerts an elastic force directed up on her. Calculate her acceleration at the instant the cord exerts an elastic force of 825 N [up] on her.

2. During a bungee jump, the velocity of the 55-kg jumper at the lowest point of her jump is zero and the cord stretches to its maximum. Compare the direction of her acceleration at the lowest point of the jump to her acceleration at the part of the jump where she is accelerating due to gravity.

Answer 1

Given the mass of jumper is 55 Kg

with a free body diagram

by newton's second law,

Fnet = ma

55a=825-539

55a=286

a=5.2 m/s^2 upward

at lowest point the change in potential energy due to earth is equal to change in potential of cord

force due to cord = kh

force due to cord = 2mg

free body diagram

Fnet = ma

2mg-mg=ma

a=g upwards

at the point when the acceleration is due to gravity

a= -g

g downwards

the direction is opposite