A helical compression spring is made with oil-tempered wire with wire diameter of 0.2 in, mean coil diameter of 2 in, a total of 12 coils, a free length of 5 in, with squared ends.
(a) Find the solid length.
(b) Find the force necessary to deflect the spring to its solid length.
(c) Find the factor of safety guarding against yielding when the spring is compressed to its solid length.