Forces
Science: KS3, topic 3.2.1
Forces
We feel forces as a push or pull. Forces happen in pairs that are equal and opposite.
Forces
- Forces happen when there is an interaction between objects.
- We feel forces as either a push or a pull.
- You can ‘push’ open a door.
- You can ‘pull’ a sleigh.
Force pairs and measuring
- We feel forces as pairs that act in opposite directions.
- Forces can be measured using a Newton metre.
- A Newton metre is also called a force metre or spring balance.
Representing forces
- Forces are measured in Newtons (N).
- We can show a force with an arrow.
- The way the arrowhead points shows the direction of the force.
- The size of the arrow shows the magnitude of the force.
Resultant forces
- The resultant force is the overall force.
- Two forces can act in the same direction.
- Then the resultant force is the sum of all the forces.
Forces in opposite directions
- Two forces can act in opposite directions.
- Then the resultant force is the difference between the forces.
Test yourself on Forces
In which units are forces measured?
Which of these are true of representing forces?
In a tug of war, one team pulls with a force of 20 N. The other team pulls in the opposite direction with a force of 15 N. What is the resultant force on the rope?