When a suction cup sticks to a wall it is
A)pulled to the wall by the vacuum.
B)pushed to the wall by the atmosphere.
C)both of these
D)none of the above

Question

Quizplus · Accepted Answer

When a suction cup is pressed against a wall or any other flat surface, the air between the two surfaces is forced out. As a result, the pressure inside the suction cup reduces, and the atmospheric pressure around the cup pushes the cup against the surface, creating a firm seal. So, it is the atmospheric pressure that allows the suction cups to stick to walls, not the vacuum. Therefore, the correct option is B, i.e., pushed to the wall by the atmosphere.

When a Suction Cup Sticks to a Wall It Is