Here are spectra for some elements common in the atmospheres of stars. Use the web to help with the viewing of the color of the elements:

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

Which of the following is not a means to accelerating? question 4 options: a)increase speed b)remain still c)decrease speed d)change direction