GCSE Physics Pressure in fluids questions by topic

Complete the sentences about pressure. (Physics only)

1. (a)Pressure = force ÷ …[1]
2. (b)Pressure is measured in …[1]
3. (c)The upward force on an object in a fluid is called …[1]
4. (d)Atmospheric pressure … as altitude increases.[1]

A box of weight 300 N stands on a base of area 2.0 m². (Physics only)

1. (a)Write down the equation for pressure.[1]
2. (b)Calculate the pressure under the box.[2]
3. (c)State the unit of pressure.[1]

Explain each design choice using pressure. (Physics only)

1. (a)Why does a sharp knife cut better than a blunt one?[2]
2. (b)Why do rescue teams use air mats rather than thin ropes when catching falling people?[2]

A wooden block floats in fresh water. (Physics only)

1. (a)State the relationship between the upthrust on the block and its weight.[1]
2. (b)State how the density of the block compares with the density of water.[1]
3. (c)The block is pushed fully under and released. Explain what happens.[2]

A 600 N pallet stands on four legs of total contact area 0.020 m². The floor is damaged above a pressure of 50 000 Pa. (Physics only)

1. (a)Calculate the pressure under the legs.[2]
2. (b)Calculate the minimum total contact area needed to keep the pressure at or below 50 000 Pa.[2]
3. (c)State one way the pallet design could achieve this.[1]

A metal block weighs 5.0 N in air and 3.6 N when fully submerged in water. (Physics only)

1. (a)Explain why the block appears lighter in water.[2]
2. (b)Calculate the upthrust.[2]
3. (c)State the weight of water displaced by the block.[1]

A sealed crisp packet is closed at sea level and taken up a high mountain. (Physics only)

1. (a)State what happens to atmospheric pressure as the packet is carried higher.[1]
2. (b)Explain why the packet puffs up.[3]
3. (c)The packet is now squeezed by less atmospheric pressure. Explain what provides the outward push.[1]

Calculate, using P = h ρ g (g = 9.8 N/kg, water ρ = 1 000 kg/m³). (Higher, Physics only)

1. (a)State what each symbol in P = h ρ g represents.[2]
2. (b)Calculate the liquid pressure at a depth of 0.80 m in water.[3]

A mercury barometer stands at 0.76 m of mercury (ρ = 13 600 kg/m³, g = 9.8 N/kg). (Higher, Physics only)

1. (a)Calculate the atmospheric pressure supported by the column.[3]
2. (b)Calculate the height of a water column the same atmospheric pressure could support (ρ water = 1 000 kg/m³).[3]
3. (c)State why mercury is preferred in barometers.[1]

A reservoir dam holds water 5.0 m deep against an inspection hatch of area 0.50 m² on the dam’s lower wall (ρ = 1 000 kg/m³, g = 9.8 N/kg). Ignore atmospheric pressure on the far side. (Higher, Physics only)

1. (a)Calculate the liquid pressure at the hatch’s depth.[2]
2. (b)Calculate the force the water exerts on the hatch.[3]
3. (c)Explain why the dam wall is made much thicker at the bottom.[2]
4. (d)State one assumption you made in (b).[1]

An ice cube of weight 0.20 N floats in a glass of water. (Physics only)

1. (a)State the size of the upthrust on the floating ice.[1]
2. (b)Explain, in terms of displaced water, why the ice floats rather than sinking.[3]
3. (c)The ice melts. State what happens to the water level in the glass, and why.[2]

A statue weighs 20 N in air but only 12 N when fully submerged in water (ρ = 1 000 kg/m³, g = 9.8 N/kg). (Higher, Physics only)

1. (a)Calculate the upthrust and the volume of water displaced.[3]
2. (b)Calculate the statue’s mass.[1]
3. (c)Calculate the statue’s density.[3]
4. (d)Deduce whether the statue is solid gold (19 300 kg/m³).[1]