The mechanical advantage of a first class lever

a) is always greater than one
b) is always less than one
c) can be greater or less than one
d) is the input force divided by the output force

Ahelical coil spring has a mean diameter of 50 mm, a wire diameter of 5.5 mm and is wound with a pitch of 10 mm. the spring steel has an ultimate strength of 1250 mpa. find the force needed to compress the spring solid and the wire stress in this condition. state whether the spring will return to its initial length.