Forces and Motion

• Science
• Secondary Education

FORCES AND MOTION

Prior Knowledge/SS questions

Can use padlet

Have you thought about ........

Why is a bowling ball harder to move than a golf

ball?

Sir Issac Newton

• One of the most brilliant scientists in history 
• Made many important
  discoveries in physics 
• Newton’s three laws of motion
• Explain  relationships between the forces acting on an object, the
  object’s mass, and its motion. 

Tell us all you know about force and motion?

Overview

Recap on Forces

1. A force is a push or pull, or any action that is able to change motion. 
2. Forces can be used to increase or decrease the speed of an object .
3. Change the direction an object is moving. 
4. Change in velocity requires force. 
5. Velocity is speed with direction

Newton First Law

An object at

rest will stay at rest and an object

in motion will stay in motion with

the same velocity unless acted on

by an unbalanced force

Inertia

 The property of an object

that resists changes in its motion.

Newton Second Law

The amount of acceleration depends

on both the force and the mass

Newton Second Law

A change in motion occurs only if a net force is exerted on an object.

A net force changes the velocity of the object, and causes it to accelerate.

If an object is acted upon by a net force, the change in velocity will be in the direction of the net force.

The acceleration of an object depends on its mass.

The more mass an object has or the more inertia it has, the harder it is to accelerate.

More mass means less acceleration if the force acting on the object is the same.

Newton Third Law

Every action force creates a reaction force

that is equal in strength and opposite in

direction. 

Acceleration

Acceleration is the rate at which your

velocity (speed with direction) changes. 

Acceleration

• If an object’s acceleration is zero, the object must be moving at a constant speed in a straight line (or stopped). 
• Acceleration occurs whenever there is a change in speed, direction, or both.

Acceleration

To calculate
acceleration, you divide the change in speed by the amount of time it  takes for the change to happen.

Acceleration = Change in speed
/Change in time 

Units of m/s²

F=ma

Force causes acceleration, and mass resists

acceleration.

The stronger the force on an object, the greater its acceleration.

The greater the mass, the smaller the acceleration for a given force 

Content on each Law

Newton Law 2 

Simulation experiment

https://phet.colorado.edu/en/simulation/forces-and-motion

https://phet.colorado.edu/en/simulation/forces-and-motion-basics

Newton law 1 experiment

https://www.stevespanglerscience.com/lab/experiments/newtons-bottle/

Progress check

Example of situation