# 10. Forces

# Success Criteria

Your learning has been successful if you can do the following:

Define acceleration and its units.

Calculate acceleration from speed and time measurements.

# Vocabulary

Learn these so you can communicate this concept well.

Average speed: Calculated by the total distance travelled divided by the total time taken for the journey.

Gradient / slope: How steep a line on a graph is.

Speed: How fast an object is moving.

Velocity: Similar to speed, but also tells us the direction in which an object is moving. It includes both speed and direction of motion.

Do Now:

Collect and complete this small 'Do Now'. Then glue into your SciPAD page 11. Use your commonsense when glueing - don't glue straight on-top of words!

Find some space on page 15 of your PESS1.2 SciPAD,

and answer the following questions:

What does each letter in CUTLASS stand for?

## What is a Force?

A force is a push or a pull or a twist.

Forces have both magnitude (size) and direction. The SI unit for measuring foce is the newton (N).

## Contact & Non-Contact Forces

There are contact forces and non-contact forces. When you push a box along the floor, there is contact. Whan a magnet attracts and pulls an iron nail towards it, there is no contact at first.

## What can Forces Do?

Forces can do the following things:

A force can stop a moving object.

A force can accelerate or decelerate a moving object.

A force can change the direction of motion of a moving object.

A force can change the shape of an object.

A force can keep an object in place.

A stationary object starts moving when a force acts on it.

## Balanced and Unbalanced Forces

If a force pushes an object to the right and another force of the same magnitude (size) pushes it to the left, these two forces will cancel each other out and we say the forces are balanced. The net force or the resultant force will be zero and the object will remain stationary. When balanced forces act on a moving objec,

# Tasks & Homework

## Task 1: PESS1.2 SciPAD

## Page 31-32 - Introduction to Forces and Forces in Pairs

## Page 33 - Balanced and Unbalanced Forces

## Page 34 - Force Problems

## Homework:

Access your own copy of this homework task on Microsoft Teams.