A beam is balanced if it is not starting to rotate about its pivot.

One unit for the turning effect of a force is the newton-metre (N m).

Another unit for the turning effect of a force is the newton-centimetre (N cm).

The turning effect of a force is called a moment.

Turning forces

Science

Gravitational force and weight

Stretching springs

Hooke's law

Stretching rubber

The force of a floor

Levers

Floating, mass and shape

Pressure

Pressure at different depths and heights

In the Particle explanations of density and pressure unit, pupils will build on this knowledge to learn how the arrangement and movement of particles in solids, liquids and gases explain density, pressure, floating and convection.

In the Forces unit, pupils learnt how to accurately describe and explain the actions of forces in a range of situations.

This unit explores forces, deformation, Hooke’s Law, moments, and work done. It covers pressure in liquids, atmospheric pressure, upthrust, and equilibrium, as well as simple machines and force-extension relationships, highlighting how forces affect motion, friction, and object deformation.

Hidden forces

Physical activity and equipment requiring safe use

a unit for the turning effect of a force for large distances

a unit for the turning effect of a force for small distances

the size of the turning effect of a force

Match the keywords and phrases to the explanations.

The weight of the people on each side must be the same.

The distance from the people to the pivot on each side must be the same.

The distances to the pivot multiplied by the weights must be the same.

They must be on the same side of the seesaw.

Which of these describes the conditions needed for two people to balance on a seesaw?

Six masses are hung 5 cm from the left on this balance beam. Where on the right side should the three masses be hung to make the beam balance?

A 4 N weight is placed 0.5 m from a pivot on a balance beam. Where should an 8 N weight be placed to balance the beam?

Starting with the largest, put the following forces and distances from a pivot into order of decreasing size of the moment they will cause.

A pupil tests different combinations of force and distance on opposite sides of a balance beam. Which rows show combinations that will balance the beam?

Which of these is **not** the result of there being a resultant force acting on an object?

Which of these objects do not make use of levers?

What name is given to the force that is applied to make a lever move?

What name is given to the force that is exerted by a lever?

Levers are often used as force __________ as they produce larger load forces than the effort force used to move them.

Which of these units can the size of the load force be measured in? 

Starter Quiz