1. Newton’s Laws of Motion
Looking at
the relationship between Force
and
Motion

2. Dogs Explain it all

3. Newton’s 1st Law of Motion (Law of Inertia)
An object at rest stays at rest and an object in motion stays in motion (at a constant speed and in a straight line) unless acted on by an unbalanced force

4. Newton’s 1st Law- Objects at Rest
An object remains at rest unless an unbalanced force acts on it.

5. Newton’s 1st Law- Objects in Motion
Objects will continue to move with the same velocity unless acted on by an unbalanced force.

6. When you ride a bus, why do you fall forward when the bus stops moving?

7. Friction and Newton’s First Law
Friction between two objects works against the motion of
the of the moving object.
Because of friction, observing the effects of Newton’s first law is often difficult.
For example, friction will cause a rolling ball to slow down and stop.

9. Inertia and Newton’s First Law
The tendency of an object to resist change in motion.
This explains how seat belts work! Can you explain it?

10. Mass and Inertia Mass is a measure of inertia
Small mass = less inertia
Large mass = more inertia
Which is easier to throw, a baseball or bowling ball? Why?
Which is easier to change the motion of, kicking a rolling soccer ball or kicking a rolling bowling ball? Why?

11. Newton’s 2nd Law of Motion
The acceleration of an object depends on the mass of the object and the amount of force applied (unbalanced force).
F=ma or a = F/m

12. 2nd Law Part 1: Acceleration depends of mass
The acceleration of an object decreases as its mass increases and that its acceleration increases as its mass decreases. Large Mass = decreasing acceleration Small Mass = increasing acceleration

13. 2nd Law part 2: Acceleration Depends on Mass
An object’s acceleration increases as the force on the object increases.
An object’s acceleration decreases as the force on the object decreases.
Increasing Force = Increasing Acceleration
Decreasing Force= Decreasing Acceleration
The acceleration of an object is always in the same direction as the force applied.

15. Expressing Newton’s Second Law Mathematically
F=ma or a = F/m

16. Math Focus

18. Newton’s 3rd Law All forces act in pairs
Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object.
All forces act in pairs

19. Action reaction Forces
Force Pairs do no act on the same object.
When a force is exerted, there is always a reaction force. A force never acts by itself.