Pressure 3

​Watch this video (3 mins)

​Make sure to understand:

• ​How to calculate liquid pressure.

Multiple Choice

Calculate the pressure exerted by the water on the fish.

[Density of water = 1 000 kg m⁻³ and g = 10N/kg]

• 5 × 10⁴ Pa

• 5 × 10⁷ Pa

• 5 × 10⁶ Pa

• 5 × 10^-1 Pa

Multiple Choice

Answer the question in the diagram.

(Hint: use 'depth', not 'height')

• A

• B

• C

• D

Multiple Choice

Given that the pressure of sea water at the bottom of an ocean is 7.65 × 10⁷ N m⁻², calculate the depth of the ocean.

[Density of sea water = 1.02 × 10³ kg m⁻³ and g = 10N/kg]

• 7.5 × 10⁸ m

• 7.5 × 10⁴ m

• 7.5 × 10³ m

• 7.5 × 10² m

​Watch this video (3 mins)

​Make sure to understand:

• ​The three factors affecting the pressure in liquids.

Multiple Choice

Which of the following does not affect the pressure beneath the surface of a liquid?

• Strength of the gravitational field

• Area of the liquid surface

• Density of the liquid

• Depth of the liquid

Multiple Choice

The diagrams show, to the same scale, the vertical sections of a set of circular vessels, each containing the same depth of water.

• The water exerts the same pressure on the base of each vessel.

• The water exerts the greatest pressure on the base of vessel S.

• The water exerts the greatest pressure on the base of vessel P.

• The water exerts the same force on the base of each vessel.

Multiple Choice

Recall that Liquid pressure depends on the depth below the surface and also depends on the density of the fluid.

Sea water is denser than Lake water.

Fish X is above Fish Y in the Lake water.

Fish Z is at the same depth as Fish Y but Fish Z is in the Sea water.

The pressure of water exerted on the fishes is P_X, P_Y and P_Z respectively.

Which comparison is correct about the pressure of water exerted on the fishes?

• P_Z > P_Y > P_X

• P_Z = P_Y

• P_X > P_Y

• P_Z < P_X < P_Y

Multiple Choice

Two identical containers containing liquid M and liquid N with 28 cm height and 20 cm height respectively. Both containers produce the same water spurt at the bottom.

If the density of liquid M is 2.0 g cm⁻³, find the density of liquid N.

(g = 10N/kg)

Hint: since both containers produce the same water spurt then the both containers have the SAME pressure at the bottom.

• 0.70 g cm⁻³

• 1.40 g cm⁻³

• 1.43 g cm⁻³

• 2.80 g cm⁻³