uppose an 82 kg person in a wheelchair is moving over rough ground At the speed they are traveling he frequency of vibration is 60 rad s and the person s displacement is 2 3 times as large as the ground s isplacement If the person moves a little faster their displacement decreases Assume the wheelchair s uspension system has negligible but non zero damping a What is the wheelchair s equivalent stiffness b Suggest a change to the wheelchair s suspension system to reduce the user s displacement Justify your answer