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# Forces as Vectors

### Forces as Vectors

Forces can be seen as a measurement of any interaction that causes an object to move and change its velocity.

Measurements used in science can be categorised as **scalar** or **vector** quantities. A scalar quantity has only **magnitude** (size). A vector quantity has both **magnitude and direction**.

Do you think **speed** is a scalar or vector quantity?

Speed is a scalar quantity.

500 mph does not have an associated direction, so speed is a scalar quantity.

Do you think **distance** is a scalar or vector quantity?

Distance is a scalar quantity.

5000 metres does not have an associated direction.

Do you think **acceleration** is a scalar or vector quantity?

Acceleration is a vector quantity.

Acceleration is a change in speed - either positive (speeding up) or negative (slowing down). That is what we think of as the "direction" of acceleration.

If **scalar** quantities have only magnitude, and **vector** quantities have both magnitude and direction, which category would you choose to describe **forces**?

A force is a push or a pull resulting from the interaction between two objects, for example when a football is pushed towards the net because your foot is kicking it. Try to select all the options below that describe the effect forces can have on objects.

You can select multiple answers

An object will remain either at rest or at a constant speed, unless it is acted on by an unbalanced force. This is why a ball will stay at rest on the ground until you kick it.

**Balanced forces** are equal in size, but act in opposite directions. If the forces acting on a moving car are **balanced**, the car would ...