Two cars of the same mass have different velocities. which car has more momentum

Ammonia enters the expansion valve of a refrigeration system at a pressure of 10 bar and a temperature of 18oc and exits at 6.0 bar. the refrigerant undergoes a throttling process. determine the temperature, in oc, and the quality of the refrigerant at the exit of the expansion valve.

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration

Achild has maximum walking speed of 1.6 m/s. what is the length of the child's legs? 0.26 m