A suction cup is pressed onto a smooth vertical wall. This pushes most of the air out from inside the cup.
The area of the suction cup is 0.0012 m2.
Atmospheric pressure is 100 000 Pa100\,000\ \text{Pa}100000 Pa. Assume that the pressure of the air left inside the cup is zero.
Explain why the suction cup stays on the wall.
Calculate the force exerted by the atmosphere on the suction cup.
The suction cup is taken to the top of a mountain, where atmospheric pressure is 70 000 Pa70\,000\ \text{Pa}70000 Pa.
A bag with a weight of 90 N is hung from the suction cup. The bag pulls the cup down along the wall.
The cup stays on the wall only if the force exerted by the atmosphere on the cup is greater than the weight of the bag.
Explain whether the cup stays on the wall at the top of the mountain.
Your answer should include a calculation.
132 exam-style questions on Edexcel GCSE Physics 15.2 Pressure in fluids, covering 15.2.1 Atmospheric pressure and height, 15.2.2 Pressure in fluids, 15.2.3 Pressure, force and area, 15.2.4 Pressure and depth, 15.2.5 Pressure in liquids: depth and density, 15.2.6 Upthrust, and 15.2.7 Floating and sinking. Each one has a worked solution and a mark scheme showing where the marks go.