1. Free Fall
The acceleration of gravity (g) for objects in free fall at the earth's surface is 9.8 m/s2.
Galileo found that all things fall at the same rate.

2. Free Fall The rate of falling increases by 9.8 m/s every second.
Height = ½ gt2
For example:
½ (9.8 )12 = 4.9 m ½(9.8)22 = 19.6 m
½ (9.8)32 = 44.1 m
½ (9.8)42 = 78.4 m

3. Free Fall
A ball thrown horizontally will fall at the same rate as a ball dropped directly.

4. Free Fall
A ball thrown into the air will slow down, stop, and then begin to fall with the acceleration due to gravity. When it passes the thrower, it will be traveling at the same rate at which it was thrown.

5. Free Fall
An object thrown upward at an angle to the ground follows a curved path called a parabola.

6. Air Resistance In air… In a vacuum A stone falls faster than a feather
Air resistance affects stone less
In a vacuum
A stone and a feather will fall at the same speed.

7. Air Resistance Free Fall
A person in free fall reaches a terminal velocity of around 54 m/s
With a parachute, terminal velocity is only 6.3 m/s
Allows a safe landing

8. Air Resistance Ideal angle for a projectile
In a vacuum, maximum distance is at an angle of 45o
With air resistance (real world), angle is less
Baseball will go furthest hit at an angle of around 40o

9. First Law of Motion
The first law of motion states: If no net force acts on it, an object at rest remains at rest and an object in motion remains in motion at a constant velocity.

10. Inertia and Mass
Inertia is the apparent resistance an object offers to any change in its state of rest or motion.

11. Second Law of Motion F = Ma
Newton's second law of motion states: The net force on an object equals the product of the mass and the acceleration of the object. The direction of the force is the same as that of the acceleration.
F = Ma

12. Second Law of Motion
A force is any influence that can cause an object to be accelerated.

13. Mass and Weight
Weight
Definition: The force with which an object is attracted by the earth’s gravitational pull
Example: A person weighing 160 lbs is being pulled towards the earth with a force of 160 lbs (712 N).
Near the earth’s surface, weight and mass are essentially the same

14. Third Law of Motion
The third law of motion states: When one object exerts a force on a second object, the second object exerts an equal force in the opposite direction on the first object.

15. Third Law of Motion
Examples of the 3rd Law

16. Circular Motion
Centripetal force is the inward force exerted on an object to keep it moving in a curved path.
Centrifugal force is the outward force exerted on the object that makes it want to fly off into space.

17. Circular Motion

18. 833 N is needed to make this turn.
Circular Motion
833 N is needed to make this turn.
If he goes too fast, which wheels are likely to come off the ground first?

19. Artificial Satellites GPS-Global Positioning Satellite
The world's first artificial satellite was Sputnik I, launched in 1957 by the Soviet Union.
GPS-Global Positioning Satellite

20. Artificial Satellites
The escape speed is the speed required by an object to leave the gravitational influence of an astronomical body; for earth this speed is about 40,000 km/h.