Pressure & Pressure Differences in Fluids Practice Questions

State the direction of the force that the water pressure exerts on the surface of the swimmer's goggles.

Calculate the pressure due to the water at a depth of $2.5\ \mathrm{m}$.

Use the equation $P = h \times \rho \times g$

The total pressure acting on the swimmer at this depth is greater than your answer to part (b).

State the reason for this.

Calculate the pressure exerted by the tractor on the ground.

Use the equation $P = \dfrac{F}{A}$

A tractor of the same weight fitted with narrow tyres sinks into the mud more easily.

Explain why.

Explain, using a simple model of the Earth's atmosphere, why atmospheric pressure decreases with height above the Earth's surface.

The atmospheric pressure outside the weather station is $62\,000\ \mathrm{Pa}$. One window of the station has an area of $0.80\ \mathrm{m^2}$.

Calculate the force exerted on this window by the outside air.

Calculate the pressure produced in the brake fluid by the small piston.

Give your answer in pascals.

The pressure exerted by the fluid on the large piston is the same as your answer to part (a).

Calculate the force exerted by the fluid on the large piston.

State how the pressure due to the water changes as the depth below the surface increases.

An inspection hatch is fitted at a depth of $3.0\ \mathrm{m}$ and a second hatch is fitted at a depth of $12.0\ \mathrm{m}$.

Calculate the difference in the pressure due to the water at these two hatches.

Explain why the dam is built much thicker at its base than at the top.

Calculate the density of the cooking oil.

Use the equation $P = h \times \rho \times g$

An identical tank is filled with water to the same depth of $1.6\ \mathrm{m}$. The density of water is $1000\ \mathrm{kg/m^3}$.

Explain why the pressure recorded at the base of this tank is greater than $12\,800\ \mathrm{Pa}$.

Calculate the upthrust acting on the stone when it is completely below the surface of the water.

Explain, in terms of pressure, why the water exerts an upthrust on the stone.

State the weight of the water displaced by the stone and give a reason for your answer.

The student lowers the stone so that it is much deeper in the water, but still completely below the surface.

State and explain what happens to the reading on the newtonmeter.

A hot air balloon is held on the ground by a rope. The envelope of the balloon holds $2200\ \mathrm{m^3}$ of hot air. The total weight of the balloon (including the hot air inside the envelope), basket, burner and passengers is $24\,000\ \mathrm{N}$.

At ground level the density of the surrounding air is $1.2\ \mathrm{kg/m^3}$. The density of the surrounding air decreases as height above the ground increases.

The rope is released and the balloon rises. It eventually reaches a steady height and stops rising.

Explain, in terms of the forces acting on the balloon, why the balloon rises when the rope is released and why it eventually stops rising.

Include calculations in your answer.

Gravitational field strength, $g$, is $10\ \mathrm{N/kg}$.

Explain why the block floats instead of sinking.

Calculate the depth $d$ of the block below the water surface.

Small metal masses are placed gently on top of the block until the block is just about to sink below the surface.

Calculate the total weight of metal that can be added.