An underwater research dome has a hemispherical shape and rests on the flat seabed, as shown in the diagram.
Which of the following statements correctly describes the force exerted by the hydrostatic pressure of the water at any point on the curved outer surface of the dome?
The force acts parallel to the seabed at all points on the curved surface.
The force is directed vertically downwards at all points on the curved surface.
The force acts at an angle of 90∘90^\circ90∘ to the tangent plane of the surface, directed towards the centre of the hemisphere.
The force acts at an angle of 45∘45^\circ45∘ to the tangent plane of the surface, directed outwards from the centre.