Worksheet 7 - Pressure

Q1. Which would be the least likely to sink into soft ground?

• A. a loaded lorry with four wheels

• B. a loaded lorry with six wheels

• C. an empty lorry with four wheels

• D. an empty lorry with six wheels

A boy is trapped in a large area of very soft mud. A man rescues the boy by crawling across a long, light board rather than by walking into the mud.

What effect, if any, does the board have on the force and the pressure on the mud, compared with walking?

• A

• B

• C

• D

The rudder of a large ship is operated hydraulically. Oil at high pressure exerts a force F on a piston that in turn moves a lever arm.

The oil is at a pressure of 500 kPa and the surface area of the piston is 0.20 m².

What is the size of F?

• A 100 N

• B 2500 N

• C 100 000 N

• D. 250 000 N

A brick of weight 80 N stands upright on the ground as shown.

What is the pressure it exerts on the ground?

• A

• B

• C

• D

The system shown in the diagram contains a liquid.

A downward force of 80 N is exerted on the piston K. What will be the upward force exerted by the liquid on piston L?

• A. 1 N

• B. 4 N

• C. 80 N

• D. 1600 N

A sink is filled to a depth of 0.20 m with a liquid of density 1100 kg/m³. The gravitational field strength is 10 N/kg.

What is the pressure on the base of the sink due to the liquid?

• A 22 Pa

• B 220 Pa

• C 2200 Pa

• D 11 000 Pa

A bottle is filled with water. A cap is put on the bottle and it is turned upside down. There is no air inside the bottle.

The area of the cap in contact with the water is 4.0 x 10^-4 m².

The density of water is 1000 kg/m³ and the gravitational field strength is 10 N/kg.

The water produces a force on the cap.

What is the value of this force?

• A. 0.075 N

• B. 0.12 N

• C. 1.2 N

• D. 13 N

The diagrams show a simple mercury barometer.

Which diagram shows the distance to be measured to find atmospheric pressure?

• A

• B

• C

• D

The diagram shows a mercury barometer.

What happens to a distance h when the mercury barometer is taken up in a balloon?

• A It decreases, because atmospheric pressure increases with height.

• B It decreases, because atmospheric pressure decreases with height.

• C It increases, because atmospheric pressure increases with height.

• D It increases, because atmospheric pressure decreases with height.

The diagram shows a simple mercury barometer. The height of the mercury column is h. Which of the following will cause h to change?

1. Evaporation of mercury from the mercury reservoir

2. Changes in the gravitational field strength

3. Replacing mercury with water

• A 3 only

• B 1 and 2 only

• C 2 and 3 only

• D 1, 2 and 3