A conical compression spring (Figure 12.6) having five active coils has a pitch of 7 mm throughout. The spring is made of 5-mm-diameter steel wire and has an active coil diameter that varies from 25 mm at the top to 55 mm at the bottom. A force is applied to compress the spring, and the stresses always remain in the elastic range.
(a) As the force is increased, which coil deflects to zero pitch first?
(b) Calculate the magnitude of force required to cause the deflection in part a.
(c) Suppose the force is increased until the entire spring is compressed solid. Neatly sketch a force-deflection diagram for the spring.
