1. Forces and Motion
Chapter 3

2. Sir Isaac Newton
Sir Isaac Newton ( ), an English physicist and mathematician, is one of the most brilliant scientists in history.
Before the age of 30, he formulated the basic laws of mechanics, discovered the universal law of gravitation, and invented calculus!

4. Newton’s Laws
Unless you apply force, things tend to keep on doing what they were doing in the first place.
Force causes an object to accelerate, while the object’s mass resists acceleration.
For every action, there is an equal and opposite reaction.

5. Force
A force is what we call a push or a pull, or any action that has the ability to change motion.
There are two units of force that are commonly used: pounds and newtons.
Scientists prefer to use newtons.

6. Mass Mass is the amount of “stuff” or matter in an object.
We can also define mass as the amount of matter an object has.
Mass is measured in kilograms.

7. Weight Weight is a force that comes from gravity pulling on mass.
The weight depends on how strong gravity is.
Earth is bigger than Mars and has stronger gravity.
A kilogram weighs 9.8 newtons on Earth but only 3.8 newtons on Mars.

8. Force Formula 𝐹=𝑚×𝑎 Newton’s Second Law: force (newtons, N) mass (kg)
acceleration (m/sec2)

9. Force Problems F = m x a F = 5kg x 2.0m/s2 F = 10N
A ball has a Mass (m) of 5 kg. How much Force (F) would I require in order to throw the ball with an Acceleration (a) of 2.0 m/s2?
F = m x a
F = 5kg x 2.0m/s2
F = 10N

10. Force Problems F = m x a 𝐹 𝑚 = a 600𝑁 200𝑘𝑔 = a a = 3 m/s2
2. A sumo wrestler has a mass of 200kg. How fast would the sumo wrestler have to move in order to move another sumo wrestler with a weight of 600N?
F = m x a
𝐹 𝑚 = a
600𝑁 200𝑘𝑔 = a
a = 3 m/s2

11. Word Walls. Word. Group 1 Group 3 Group 2 Group 4 Air Friction
Equilibrium
Force
Friction
Gravity
Group 3
Newton
Newton’s first law
Newton’s second law
Newton’s third law
Pounds
Group 2
Inertia
Law of conservation of momentum
Mass
Momentum
Net force
Group 4
Rolling friction
Sliding friction
Viscous friction
weight