an engine manufacturer makes the claim that the engine they have developed will, on each cycle, take 100 j of heat out of boiling water at 100°c, do mechanical work of 80 j, and exhaust 20 j of heat at 10°c. what, if anything, is wrong with this claim?

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.