Newtons third law of motion
the lab questions are in the paper

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.

Two identical stars with mass m orbit around their center of mass. each orbit is circular and has radius r, so that the two stars are always on opposite sides of the circle. (a) find the gravitational force of one star on the other. (b) find the orbital speed of each star and the period of the orbit. (c) how much energy would be required to separate the two stars to infinity?

If water vapor with the mass of 35.0 grams is cooled and condensed into water in a closed system such as a closed glass jar, what is the mass of the water after the water vapor completely condenses? a) 34.5 grams b) 35.0 grams c) 35.5 grams d) the mass cannot be determined without knowing the volume