Suppose an 82 kg person in a wheelchair is moving over rough ground. At the speed they are traveling, the frequency of vibration is 60 rad/s and the person's displacement is 2.3 times as large as the ground's displacement. If the person moves a little faster, their displacement decreases. Assume the wheelchair's suspension 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. Suppose an 82 kg person in a wheelchair is moving over rough ground. At the speed they are traveling, the frequency of vibration is 60 rad/s and the person's displacement is 2.3 times as large as the ground's displacement. If the person moves a little faster, their displacement decreases. Assume the wheelchair's suspension 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.