The force that stretches the cord is the weight of the bungee jumper, which is given by:
[tex]F=mg[/tex]
where m is the mass of the jumper and g the gravitational acceleration. Substituting, we find
[tex]F=mg=(68 kg)(9.81 m/s^2)=667.1 N[/tex]
This force is equal to the elastic force that stretches the cord:
[tex]F=kx[/tex]
where k is the spring constant and x is the elongation of the cord. Rearranging the equation, we find x:
[tex]x= \frac{F}{k}= \frac{667.1 N}{54 N/m}=12.4 m [/tex]
