Ahousehold refrigerator that has a power input of 450 w and a cop of 1.65 is to cool five large watermelons, 10 kg each, to 8°c. if the watermelons are initially at 28°c, determine how long it will take for the refrigerator to cool them. the watermelons can be treated as water whose specific heat is 4.2 kj/kg·°c. is your answer realistic or optimistic? a

Water at 70°f and streams enter the mixing chamber at the same mass flow rate, determine the temperature and the quality of the exiting stream. 0 psia is heated in a chamber by mixing it with saturated water vapor at 20 psia. if both streams enters the mixing chamber at the same mass flow rate, determine the temperature and the quality of the existing system.

Thermal stresses are developed in a metal when its a) initial temperature is changed b) final temperature is changed c) density is changed d) thermal deformation is prevented e) expansion is prevented f) contraction is prevented

The flow rate of air through a through a pipe is 0.02 m5/s. a pitot static tube is placed in the flow. the radius of the pitot static tube is 1 mm. assuming the flow to be steady and the air to be at 300k, calculate the difference in total and static pressure if the diameter of the pipe is: (a) d 0.1 m d 0.05 m (c) d 0.01 m