2. Find the electrostatic force between two protons that are 2.0 m apart. The elementary charge of
a proton is 1.602 x 10-19 C.

Oxygen undergoes an isentropic expansion from 120 degree c and 280 kpa absolute to 140 kpa absolute. determine the final temperature of the oxygen and the amount of work per kg of o_2 produced in the process if it is adiabatic.

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?

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.