Pressure

An ancient wooden treasure chest has sunk to the bottom of the sea.

Explain why the forces acting on the treasure chest cause it to remain stationary on the seabed.

[3 marks]

• What forces are acting?

  • Normal Contact force from the seabed acts upwards

  • Upthrust (from water pressure difference at the top and bottom of an object) acts upwards

  • Weight of chest downwards

  Weight = Normal + Upthrust

  So Resultant force is zero.