1. Chapter 11 Forces
11-1 Laws of Motion

2. Who is Newton?
Sir Isaac Newton – described the relationship between motion and force
Newton - sitting under an apple tree, an apple fell on his head, and he suddenly thought of the Universal Law of Gravitation.

3. Newton
Newton - sitting under an apple tree, an apple fell on his head, and he suddenly thought of the Universal Law of Gravitation.
Force – measured in Newtons (N)

4. Newton’s First Law Newton’s 1st Law –
An object as rest will remain at rest and an object in motion will stay in motion unless acted on by an outside force.
Also called the law of inertia

5. Inertia
Inertia – Tendency of an object to resist a change in motion

6. Law of Inertia Law of Inertia – Mass and Inertia are directly related
The More mass the More inertia
The less mass the less inertia

7. Newton’s Second Law
The amount of force acting on an object equals the object’s mass times its acceleration.

8. Newton’s 2nd Law Force = Mass x Acceleration F = M x A A = F / M
M = A / F
Newton (N) – Unit of measurement for Force
1 Newton = 1 kg x 1 m/s²

10. Newton’s 2nd Law
If you throw a softball and a baseball as hard as you can, why don’t they have the same speed?

11. 2nd Law Practice
What is the acceleration of a boy on a skateboard if the unbalanced forward force on the boy is 15 N? The total mass of the boy and the skateboard is 58 kg.
What force is necessary to accelerate a 1250 kg car at a rate of 40 m/s2?
What is the mass of an object if a force of 34 N produces an acceleration of 4 m/s2?