# May the Force Be With You!

## Presentation on theme: "May the Force Be With You!"— Presentation transcript:

May the Force Be With You!

What is FORCE? A push or pull on an object
Causing resting objects to move Causing moving objects to accelerate

Two Main Force Types Balanced Forces Unbalanced Forces Two Forces
Opposite directions Both are equal in value No movement (stationary) Unbalanced Forces Two Forces One greater than the other Opposite directions Movement

Newton’s 3 Laws of Motion

1st Law of Motion The Law AKA
Objects at rest remain at rest or objects in motion remain in motion unless acted on by a force AKA Law of INERTIA

1st Law of Motion Inertia—force that is resistant to the direction of motion Concept—unbalanced forces Ex: inertia belts (seat belts) Space ships going through space

2nd Law of Motion The Law Concept AKA
The acceleration of a body depends on the ratio of the acting force to the mass of the body Concept Unbalanced forces AKA The force formula

F= force (unit = Newton) a= acceleration (unit m/s2
Force Formula Force = mass * acceleration F= m*a F= force (unit = Newton) m= mass (unit = kg) a= acceleration (unit m/s2

Force Example Problems
#1 How much force is needed to accelerate a 500-kg car at a rate of 4 m/s/s? #2 A 50-kg object is accelerating at a rate of 2 m/s/s, what is the force that caused this acceleration?

3rd Law of Motion The Law Concept Ex Remember, forces are equal
For every action there is an equal but opposite reaction Concept Balanced Forces Ex Stationary Objects Rockets being launched Remember, forces are equal but opposite

Applying the 3rd Law If Rico kicked a ball with 100-N of force, how much force did the ball exert on Rico?

What is Friction? Is a force that resist motion and can cause heat
Allows us to walk, drive a car, play sports Lubricants help reduce friction

4 Types of Friction Rolling Friction Static Friction Fluid Friction
Friction acting on objects that are rolling Ex: car tired Fluid Friction Friction acting on objects going through a fluid Fluid—liquid or gas Ex: swimming or air resistance Static Friction Friction force on stationary objects Ex: book sitting on desk Sliding Friction Friction acting on objects sliding over a surface Ex: pushing a box

ID the type of Friction

What is Gravity? A force that acts between masses Acts downward
Acceleration due to gravity (on Earth)= 9.8 m/s/s

What is Air Resistance? Force that slows down falling objects Factors
Atmosphere Surface area of object Acts upward

Gravity and Air Resistance: A Relationship
They are opposite forces Gravity goes down Air resistance acts up Follows Newton’s 3rd Law of Motion

Feather vs. Rock EARTH Moon or Vacuum Feather floats down
Rock falls at 9.8 m/s/s Why? Air Resistance Moon or Vacuum Feather and rock fall at the same rate WHY? No air so no air resistance

Projectile Motion The motion of falling objects throw forward
Two forces Gravity Forward velocity Gravity acts down Velocity acts forward Forms a curve path

Weight Is the force of gravity acting on an object
Weight Formula Weight = mass * gravity Fg = m * g Fg= weight (unit = N) m= mass (unit = kg) g= gravity (9.8 m/s/s)

Weight Example Problems
#1 If a 20 kg dude is on Earth, what is his weight? #2 A rock on Earth has a weight of 1000 N, what is the rock’s mass?