John rapidly pulls a plunger out of a cylinder.As the plunger moves away,the gas molecules bouncing elastically off the plunger are
A)rebounding at a higher speed than they would have if the plunger weren't removed.
B)rebounding at a lower speed than they would have if the plunger weren't removed.
C)rebounding at the same speed as they would have if the plunger weren't removed.
D)Whether they speed up or slow down depends on how fast the plunger is removed.

Question

Quizplus · Accepted Answer

As John pulls the plunger out of the cylinder, the volume of the cylinder increases, and therefore the pressure decreases. According to the ideal gas law, PV=nRT, if the pressure decreases, the gas molecules will have more space to move around in and, as a result, will decrease their speed. Therefore, the gas molecules bouncing elastically off the plunger will rebound at a lower speed than they would have if the plunger weren't removed.

John Rapidly Pulls a Plunger Out of a Cylinder