Forces

1
Forces

• A force is defined as a push or a pull that acts
  on an object.

2
Characteristics of a Force

• wants to change the motion of an object
• has size
• has direction
• can change speed
• can change direction

3
SI unit of Force Newton

• A Newton is a metric unit of weight
• 1 Newton 1 kg m/s2

4
Force of Gravity

• Force of gravity is the downward force exerted by
  the earth on an object.
• Force mass x acceleration due to gravity
• F ma
• Acceleration due to gravity 9.8 m/s2

5
Contact vs Non-contact

• Contact there is contact between what is
  exerting the force and what is receiving the
  force
• Non-contact the result is visible but you
  cannot see the contact between the force and the
  agent, example gravity

6
Net Force

• combination of all of the forces
• determined by the directions of the forces
• shown by vectors

7
Vector

• arrow attached to the receiver of the force
• length magnitude of the force
• direction shown by the arrow head
• ?, ?, ?, ?

8
Net force

• Forces in the same direction add the forces
  together
• Forces in different directions subtract the
  smaller force from the larger one

9
Balanced Forces

• net force 0
• no change in motion
• an object at rest will stay at rest

10
Unbalanced Force

• Net force ? 0
• change in speed
• change in direction
• object at rest will move
• object moving might stop