Forces in Motion

1
Forces in Motion

• Chapter 2

2
Questions

• How does the force of gravity affect falling
  objects?
• What is projectile motion?
• What are Newtons laws of motion?
• What is momentum?

3
Falling Objects

• Mass of an object does not affect the rate at
  which it falls.
• All objects fall with the same rate of
  acceleration due to gravity

4
Accelerating at a Constant Rate

• All objects accelerate toward the Earth at a rate
  of 9.8 m/s/s

5
Air Resistance

• definition fluid friction that opposes the
  motion of objects through air.
• Slows Down Acceleration
• Affects some objects more than others. (size and
  shape)

6
Bungee Jumping
7
Effects of air resistance on downward
acceleration of a falling object
The force of air resistance
Net force on the object
The force of gravity
8
Acceleration stops at terminal velocity
9
Terminal Velocity

• As speed the amount of Air resistance
• As the object falls, upward forces of air
  resistance increases until downward force of
  gravity
• Net force is zero
• Objects stops accelerating
• Object falls at constant velocity, which is its
  terminal velocity

10
Free fall

• When there is no air resistance then there is
  free fall.
• Only force is force of gravity acting on the
  object.

11
Apollo 15 Testing Free Fall
12
Orbiting

• Objects are in Free Fall
• Two motions combine to cause orbiting
• Moving forward
• Free fall toward Earth

13
Projectile Motion

• Curved path an object follows when thrown or
  propelled near the surface of the Earth.
• Examples

14
Projectile Motion
15
Projectile Motion

• Two independent parts horizontal and vertical
• Horizontal the force applied to move it
  forward. Motion parallel to the ground
• Vertical gravity pulling on the object

16
Explain

• Explain why a ball moves in a straight lines as
  it rolls across a table but follows a curved path
  once it rolls of the edge of the table.