Newton's Laws, bungee jump problem

AI Thread Summary
A 55-kg bungee jumper experiences a downward acceleration of 7.6 m/s², prompting a calculation of the force exerted by the bungee cord. The forces involved include gravity acting downward and the bungee cord's force acting upward. The net force equation is established as Fnet = Fb - mg = ma, leading to the conclusion that Fb = m(-a) + mg. The calculated force exerted by the bungee cord is 121 N upward. The provided solution is confirmed to be correct.
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Please help me with this problem. many thanks :)

A 55-kg bungee jumper has fallen far enough that her bungee cord is beginning to stretch and resist her downward motion. Find the force (magnitude and direction) exerted on her by the bungee cord at an instant when her downward acceleration has a magnitude of 7.6 m/s^2. Ignore the effects of air resistance.

This is my work and answer. Other students are getting all sorts of different answers than me. Am I doing something wrong? Or is my work correct? Thank you so much!

The forces acting upon her are gravity downward, and the force of the bungee cord (Fb) which pulls her back in the upward direction.

Fnet = Fb - mg = ma

We know that she is experiencing an acceleration of 7.6 m/2^s in the downward direction. Thus:

Fb - mg = m(-a)
Fb = m(-a) + mg
Fb = (55)(-7.6) + 55(9.8)
Fb = 121 N upward

Thank you again for looking!
 
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Your result looks fine.
 
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