Question

a bungee jumper whit mass 65. kg jumps from a high bridge. after reaching his lowest point. he oscillates up a down, hitting a low point eight more times in 38.0 s. he finally comes to rest 25.0 m below the level of the bridge. calculate the spring stiffness constant and the unstretched length of the bungee cord.

Answer 1

A bungee jumper mass m is = 65.0 kg

the time period is T = 38.0s / 8

                                              = 4.75s

                                 T = 2π√ (m /k )

                                 4.75s = 2π √ 65.0 / k

         spring constant k = 113.6 N/m

            let the unstreched length is L

     then the extension in the cord is x = mg / K

                                                            = 65.0 kg * 9.8 / 113.6

                                                            = 5.6 m

   unstreched length of the bungee jump cord is L = 25 - 5.6 m

                                                                            = 19.3 m