If a book has a a mass of 2 kg, how much does the book weigh? Group of answer choices
A. 20 N
B. 19 N
C. 21 N
D. 22 N

Which simple machine is not part of this compound machine? a. lever b. pulley c. inclined plane d. wheel and axle

An insulated 40 ft^3 rigid tank contains air at 50 psia and 120°f. a valve connected to the tank is now opened, and air is allowed to escape until the pressure inside drops to 25 psia. the air temperature during this process is kept constant by an electric resistance heater placed in the tank. determine the electrical work done during this process.

6–43 a food department is kept at 2128c by a refrigerator in an environment at 308c. the total heat gain to the food department is estimated to be 3300 kj/h and the heat rejection in the condenser is 4800 kj/h. determine the power input to the compressor, in kw and the cop of the refrigerator.