A 70 kg gymnast sitting I a trampoline causes it to sag .10 m at the center. (A) calculate an effective force constant for the trampoline. (B) the trampoline is pulled downward an extra .05 m by a strap sewed under the center of the trampoline. When the strap is release, what is the energy and frequency of vibration of te trampoline? Ignor the mass of material that is stretches.