1. Two small cars are connected by a spring of negligible mass. Both cars are moving in the positive direction at 2.5 m/s. Car A has a mass of 2.4 kg. The spring pushes the masses apart and, after the spring expands, Car A is moving
at 3.1 m/s in the positive direction and Car B is moving at 2.1 m/s in the positive direction. Assume the track to be
frictionless and horizontal and that there are no net forces external to the system.
A. What is the mass of Car B?
B. What was the impulse that acted on Car A?
C. What was the net work done on car A?

What occurs during a combustion reaction

Refrigerant-134a flows through a carnot heat pump cycle at 0.5 kg/s. it is known that the maximum absolute temperature in the cycle is 1.1 times the minimum absolute temperature, and the net power input to the cycle is 2.5 kw. if the refrigerant changes from a saturated vapor to a saturated liquid during the heat rejection process, determine the maximum magnitude of the enthalpy of vaporization for this process in kj/kg (with 3 significant figures).

The frequency of a tuning fork can be found by the method shown. a long tube open at both ends is submerged in a beaker of water, and the vibrating tuning fork is placed near the top of the tube. the length l of the air column is adjusted by moving the tube vertically. the sound waves generated by the fork are reinforced when the length of the air column corresponds to one of the resonant frequencies of the tube. the smallest value for l for which a peak occurs in sound intensity is 7 cm. l what is the frequency of the tuning fork? the speed of sound in air is 345 m/s. answer in units of hz