Water is heated at a rate of 10 kg/s from a temperature of 15°c to 35°c by passing it through five identical tubes, each 5.0 cm in diameter, whose surface temperature is 60.0°c. estimate (a) the steady rate of heat transfer and (b) the length of tubes needed to accomplish this task.

Aspring has a relaxed length of 33 cm (0.33 m) and its spring stiffness is 6 n/m. you glue a 76 gram block (0.076 kg) to the top of the spring, and push the block down, compressing the spring so its total length is 15 cm. you make sure the block is at rest, then at time t=0 you quickly move your hand away. the block begins to move upward, because the upward force on the block by the spring is greater than the downward force on the block by the earth. calculate y vs. time for the block during a 0.09-second interval after you release the block, by applying the momentum principle in three steps each of 0.03-second duration.