[Force] [Magnets] [Friction] [Gravity and Upthrust]


Gravity is a downward force.

Gravity gives everything weight.



A block of wood resting on the table

The direction of pull on each of the four men is always towards the centre of the earth.

Usually the direction of gravity is always DOWN as shown by the block of wood.

Notice that the direction of a force is always shown by an arrow
that always points away from the object


Whenever something is in water, or trying to float, there is a force called upthrust on it.

Upthrust always pushes UP (just llike gravity always pulls down)


Here is a diagram of a ball floating on water

There are two forces on the ball

Gravity pulls down and

Upthrust pushes up

If the ball does not move up or down then these two forces are equal.


An object will float when the push of upthrust is LESS than the pull of gravity
(and sink when the pull of gravity is graeter than the upthrust)