A close-coiled helical spring is required to absorb 225 x

Question

Question - A close-coiled helical spring is required to absorb 2.25 x l0³ joules of energy. Determine the diameter of the wire, the mean diameter of the spring and the number of coils necessary if

(a) The maximum stress is not to exceed 400 MN/m²;

(b) The maximum compression of the spring is limited to 250 mm;

(c) The mean diameter of the spring can be assumed to be eight times that of the wire.

For the spring material G = 70 GN/m².