Water is heated at a rate of 10 kg/s from a temperature of 15â°c to 35â°c by passing it through five identical tubes, each 5.0 cm in diameter, whose surface temperature is 60.0â°c. estimate

(a) the steady rate of heat transfer and
(b) the length of tubes needed to accomplish this task.

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.