A barge is a boat with a flat, horizontal base. The base of the barge has an area of 40 m2.
The barge floats at rest in river water. The base of the barge is 0.80 m below the surface of the water.
The density of the river water is 1000 kg/m3. The gravitational field strength, ggg, is 10 N/kg.
Calculate the pressure due to the water on the base of the barge.
Use the equation
P=h×ρ×gP = h \times \rho \times gP=h×ρ×g
Calculate the upward force exerted by the water on the base of the barge.
State the weight of the barge.
The barge sails from the river into the sea. The density of seawater is 1025 kg/m3. The weight of the barge does not change.
Explain whether the barge floats higher or lower in the seawater than in the river water.
132 exam-style questions on Edexcel GCSE Physics 15.2 Pressure in fluids, covering 15.2.1 Atmospheric pressure and height, 15.2.2 Pressure in fluids, 15.2.3 Pressure, force and area, 15.2.4 Pressure and depth, 15.2.5 Pressure in liquids: depth and density, 15.2.6 Upthrust, and 15.2.7 Floating and sinking. Each one has a worked solution and a mark scheme showing where the marks go.