I need help quickly please!!! When air masses collide, changing weather patterns often occur at the boundaries between air masses. Meteorologists refer to this as a .

(Sorry if I got the subject wrong)

The difference between a red shift and a blue shift has to do with wavelength frequency. t or f

2kg of refrigerant 134a undergoes a polytropic process in a piston-cylinder assembly from an initial state of saturated vapor at 2 bar to a final state of 12 bar, 80 degree c. a)determine the work for the process in kj. b)sketch the process on a p-v diagram.

The seven sisters, seven stars located more than 400 light-years away in the taurus constellation can be seen here with venus and another constellation, orion. the seven stars stay grouped together but seem to move, like the planet venus. why do stars seem to move like planets in the night sky?