Sir Isaac Newton English physicist & mathematician …he developed the 3 laws of motion Motion is any change in position! p. 45 Click here

Forces Forces Forces can have the ability to change motion!!! Forces can have the ability to change motion!!! a push or a pull a push or a pull Unit: Newton (N) p. 46

Force Amount of matter (resists forces) p. 47 vs. Mass Mass

Newton’s 1st Law (Law of Inertia) “An object in motion wants to stay in motion, an object at rest wants to stay at rest.” FYI- Inertia depends upon mass. Sir Isaac Newton’s 3 Laws of Motion: p. 48

“Acceleration occurs in the direction of the force.”  the object’s mass… and also the size of the force… determine the object’s acceleration Newton’s 2nd Law (Law of Acceleration) p. 49

Formula: Formula: - Acceleration (m/s 2 ) Force (N) Mass (Kg) Ex.) p. 49, 50 Newton’s 2nd Law (calculating acceleration) p. 49 A =F/ m

Types of Forces  Forces cause motion  Motion depends on net force p. 51 Forces can be balanced or unbalanced

Balanced Forces Like a tie in an arm wrestling match!  Equal in size  Opposite in direction  No motion occurs! (equilibrium ) p. 51

Unbalanced Forces  Opposite in direction  2nd law  2nd law: unbalanced forces cause acceleration  Unequal in size p. 51

Gravity pulls everything down with a force of 9.8 N (Newtons) Gravity p. 52 downward  A force that pulls us downward toward the center of the Earth. Click here

 The gravitational force felt by an object is related to its mass.  Mass does NOT change, but your weight will change with a change in gravity (moon)!

mass x gravity (force) mass x gravity (force)Mass Amount of matter (resists forces) p. 53 vs. Weight Weight

Formula: Formula: - FwFwFwFw = mg Weight force (N) Mass (Kg) Gravity (9.8 m/s 2 ) p. 53 Calculating Weight

Friction opposes an object’s motion opposes an object’s motion 1. Air friction 2. Viscous friction 3. Sliding friction 4. Rolling friction p. 54 Four Types of Friction:

Also called Air resistance (aerodynamics reduce the air friction ) 1. Air Friction  Ex) falling objects or airplanes p. 54

Moving through a liquid, or fluid 2. Viscous Friction  Ex) swimming p. 54

3. Sliding Friction Two surfaces rub against one another  Ex) rubbing hands or clapping Caused by irregularities in the surface p. 54

An object rolls over a surface 4. Rolling Friction  Ex) ball bearings, roller skates, or wheels p. 54 Figure 3.9

“For every action, there is an equal and opposite reaction.” “For every action, there is an equal and opposite reaction.” Newton’s 3rd Law (Action /Reaction) Newton’s 3rd Law (Action /Reaction) p. 57

Formula: P = mv Momentum (Kg-m/s) Mass (Kg) Velocity (m/s) p. 58 Calculating Momentum

Total amount of momentum can not change Law of Conservation of Momentum p. 58 ex.) p. 59