Which statement describes friction? O It is perpendicular to the surfaces that rub together.
O It causes a change in motion.
O It occurs in the same direction as the push force.
O It pulls downward on a moving object.

Alidded glass container is filled with a colored gas. after a period of time, it is observed that the gas is uniformly spread throughout the box and that the movement has slowed considerably. next, a warm iron plate is carefully placed under the box. why is there resumed movement of the gas in the container?