Figure to the left shows a child's toy called a pogo stick. The child stands on the pads, applying half her weight on each side. She jumps up off the ground, holding the pads up against her feet, and bounces along with the spring cushioning the impact and storing energy to help each rebound. Assume a 60-lb child and a spring constant of 100 lb/in. The pogo stick weighs 5 lb. Design the helical compression spring to survive jumping 2 in off the ground for a finite life of 5E4 cycles. Music wire (ASTM A228) will be used. The maximum force is 224.2 lbf. The minimum force of holding the pads against the feet is 20 lbf. Choose set removed unpeened wire with diameter of 0.281 in. Choose spring index C of 7. (1) Calculate the dynamic safety factor. (2) Calculate the safety factor at shut height. (3) Check for buckling. (4) Determine the fundamental natural frequency of the system. e W/2 ALIENWARE