Newton's Laws of Motion: Definitions, Explanations, and Examples

What is Newton's 1st Law

Law of Inertia

What is Newton's 2nd Law

Law of Force and Acceleration

What is Newton's 3rd Law

Law of Action and Reaction

Explain Newton's 1st Law - Law of Inertia

A body continues in it's state of rest or motion in a straight line unless acted upon by an external force

Moving objects don't just spontaneously:

• speed up

• slow down

• change direction

Example of Newton's 1st Law - Law of Inertia

A football stays at rest until a player hits it

Explain Newton's 2nd Law - Law of Force and Acceleration

The rate of change of momentum of a body is directly proportional to the force causing it + the change takes place in the direction in which the force acts

Example of Newton's 2nd Law - Law of Force and Acceleration

Cyclist applies a greater force on the pedal to increase speed

What equation links to Newton’s 2nd Law - Law of Force and Acceleration

Force = Mass x Acceleration

Explain the equation linked to Newton’s 2nd Law - Law of Force and Acceleration

• Mass is constant

• In order to accelerate a greater force must be applied

• Force produced by muscular contraction and ground reaction force

• Greater force applied = greater acceleration

Explain Newton’s 3rd Law - Law of Action and Reaction

For every action there is an equal + opposite reaction

• Athletes push force into the ground

• Ground applies equal + opposite force back into the athlete