Pressure & Pressure Differences in Fluids Practice Questions

Which equation links area of a surface ($A$), the force normal to that surface ($F$) and pressure ($p$)?

Tick one box.

• $p = F \times A$
• $p = \dfrac{A}{F}$
• $p = \dfrac{F}{A}$
• $p = F \times A^2$

The water in the tank exerts a force on the viewing window.

State the direction of this force relative to the surface of the window.

The force of the water on the window is $6300\ \mathrm{N}$.

The area of the window is $0.90\ \mathrm{m^2}$.

Calculate the pressure of the water on the window.

Pressure = ................... Pa

Describe a simple model of the Earth's atmosphere.

State what causes atmospheric pressure on the surface of a building.

The pressure due to the oil is greater at point $B$ than at point $A$.

Explain why.

The oil is poured away and the container is filled to the same level with a liquid of greater density.

State the effect this has on the pressure at point $B$.

A nurse pushes the plunger of a syringe with a force of $15\ \mathrm{N}$.

The force acts normal to the flat surface of the plunger.

The area of this surface is $1.2\ \mathrm{cm^2}$.

Calculate the pressure produced in the liquid in the syringe.

Give your answer in standard form.

Give the unit.

Pressure (in standard form) = ................... Unit ...................

Calculate the pressure due to the water at the bottom of the lock gate.

Pressure = ................... Pa

Calculate the difference in the pressure due to the water between a point $1.5\ \mathrm{m}$ below the water surface and the bottom of the lock gate.

Difference in pressure = ................... Pa

The lock gates are made much thicker at the bottom than at the top.

Explain why.

Explain, in terms of the liquid above the sensor, why the pressure increases as the depth increases.

The student repeats the experiment using liquid $X$.

At a depth of $0.20\ \mathrm{m}$ in liquid $X$ the sensor reads $2548\ \mathrm{Pa}$.

Calculate the density of liquid $X$.

Density = ................... $\mathrm{kg/m^3}$

State what is meant by upthrust.

Explain why the empty box floats but the box filled with sand sinks.

Explain why the water produces an upthrust on the cube.

Calculate the upthrust on the cube.

Upthrust = ................... N

The mass of the cube is $6.0\ \mathrm{kg}$.

The cube is released.

Deduce what happens to the cube.

Explain why the atmospheric pressure at the summit is lower than the atmospheric pressure at the car park.

One walker carries a sealed bag of crisps. The flat top surface of the bag has an area of $1.5 \times 10^{-2}\ \mathrm{m^2}$.

The atmospheric pressure at the car park is $101\ 000\ \mathrm{Pa}$.

The atmospheric pressure at the summit is $70\ 000\ \mathrm{Pa}$.

Calculate the decrease in the force of the atmosphere on the top surface of the bag as the walker climbs from the car park to the summit.

Decrease in force = ................... N