1. The Laws of motion

2. KEY CONCEPTS AND QUESTIONS- objectives
What are some contact forces and some noncontact forces?
What is the law of universal gravitation?
How does friction affect the motion of two objects?
What are the different types of friction?

3. VOCABULARY force friction contact force noncontact force gravity mass
weight

4. GRAVITY AND FRICTION Force- a push or pull applied to an object. (N)
Contact - a force on one object by another object that is touching it.
Noncontact – a force applied to an object without touching it- gravity, electric force, magnet to metal

5. GRAVITY
Attractive force that exists between all objects that have mass.
Law of Universal Gravitation – The strength of the gravitational force depends on the mass and distance of each object.
WEIGHT- The gravitational force exerted on an object (measured in Newtons)

6. FRICTION TYPE OF FRICTION DESCRIPTION EXAMPLE STATIC
TWO SURFACES ARE NOT MOVING PAST EACH OTHER
PUSHING HEAVY OBJECT
SLIDING
TWO SURFACES SLIDE PAST EACH OTHER
SLEDDING DOWN A HILL
ROLLING
ROLLING OBJECT AND SURFACE IT ROLLS UPON
SKATEBOARD MOVING ON GROUND
FLUID
OBJECT MOVES THROUGH A FLUID- GAS OR LIQUID
SKYDIVING
FRICTION
IT IS A FORCE THAT RESISTS THE MOTION OF TWO SURFACES THAT ARE TOUCHING

7. AIR RESISTANCE
IS A FRICTION-LIKE FORCE THAT OPPOSES MOTION OF OBJECTS THAT MOVE THROUGH AIR. DEPENDS ON SPEED, SIZE, AND SHAPE OF OBJECT.