1. Chapter 6
Forces in Motion

2. 6-1 Gravity and Motion Objects Falling
All objects fall with the same acceleration
Gravity Constant
9.8 m/s2 on Earth
To fin the Velocity of an object you must use this equation
V = g * t

3. 6-1 Gravity and Motion
Find the Velocity of a penny that is dropped after it falls for 2 seconds
A rock hits the ground after falling for 4.5 seconds, what is the velocity?

4. 6-1 Gravity and Motion Air Resistance
fluid friction between the air and the object
slows down acceleration
will affect objects differently

5. 6-1 Gravity and Motion Terminal Velocity
the point where acceleration stops
the upward force of air resistance matches the downward force of gravity
= a net force of 0 N

6. 6-1 Gravity and Motion Free Fall occurs with no air resistance
all objects will fall at same acceleration

7. 6-1 Gravity and Motion Orbiting Objects are in free fall
object moves forward but is pulled by a larger object
smaller object path is curved by gravity of larger object

8. 6-1 Gravity and Motion Orbiting Objects centripetal force
unbalanced force that causes object to move in a circular path
constantly changing direction there for is always accelerating

9. 6-1 Gravity and Motion Projectile Motion
the curved path an object follows when thrown or propelled near the surface of the Earth
2 Components
Horizontal Motion
Vertical Motion

10. 6-1 Gravity and Motion Projectile Motion Horizontal Motion
the motion that is parallel to the ground
Baseball
once you throw the ball there is now more horizontal force on the ball
ball’s horizontal velocity is constant once it leaves your hand

11. 6-1 Gravity and Motion Projectile Motion Vertical Motion
the motion perpendicular to the ground
acts on all falling objects

12. 6-2 Newton’s Laws of Motion
Newton’s First Law of Motion (Law of Inertia)
States that an object at rest will remain at rest and an object that is moving at constant velocity will continue moving at constant velocity unless acted upon by an unbalanced force

13. 6-2 Newton’s Laws of Motion
Friction
The unbalanced force that will stop motion
Will change the motion of an object in the direction of the friction

14. 6-2 Newton’s Laws of Motion
Newton’s First Law of Motion (Law of Inertia)
Inertia
The tendency of an object to resist change in its motion
The greater the mass the greater the inertia
The greater the velocity the greater the inertia

15. 6-2 Newton’s Laws of Motion
Newton’s Second Law of Motion
The net force on an object is equal to the product of its acceleration and its mass

16. 6-2 Newton’s Laws of Motion
Newton’s Second Law of Motion
Force = Mass x Acceleration
Unit is the Newton (N)=kg x m/s2
Acceleration = Force / Mass
A 68 kg water-skier is being pulled by a speedboat. The force causes her to accelerate at 2 m/s2. Calculate the net force that causes this acceleration.
Force = Mass x Accel
Force = 68 kg x 2 m/s2
Force = 136 kg x m/s2
Force = 136 N

17. 6-2 Newton’s Laws of Motion
Changes in Force and Mass
How to change acceleration?
If Force goes up accel goes up
If force goes down accel goes down
If mass goes up accel goes down
If mass goes down accel goes up