Topic Menu

Cyber-chess a chess instruction site

GCSE Questions: Pressure, buoyancy, upthrust and fluids

Q3. The diagram shows an unusually shaped container. The container has four vertical tubes of different shape and size.

(a) Water is poured into the container up to the level shown in tube 1. Complete the diagram to show the height of the water in tubes 2, 3 and 4.

[1 mark]

(b) The further a swimmer dives below the surface of the sea, the greater the pressure on the swimmer. Explain why.

As he dives deeper, he increases the height/mass/volume of the water column above himself. This increases the weight/force of water pressing down on the swimmer.

[2 marks]

(c) A person swims from a depth of 0.50 m to a depth of 1.70 m below the surface of the sea.

Given that:

the density of the sea water = 1030 kg/m3 and that

the gravitational field strength = 9.8 N/kg,

calculate the increase in pressure on the swimmer as he dives deeper.

Δ pressure = Δ depth x density of liquid x gravitational field strength

Δp = Δhρg

increase in depth = 1.70 - 0.50 = 1.20 m

Δp = 1.20 × 1030 × 9.8

Δp = 12,112.8 pascals

Δp = 12,000 Pa (or 12 kPa)

the answer should be to 2 significant figures as values were only given to that precision - but at GCSE that is not expected of you

if you put 'pa' instead of Pa you did not get the mark for the unit - learn your units properly...

[4 marks]

[7 Marks TOTAL]