Lesson 1 Force

• Push and pull of an object


  Force
• the former name of spring balance

  Spring scale
• Who invented the spring balance

  Robert Hooke
• What is the unit of force?

  Newton
• the unit of force was named in honor of:

  Sir Isaac Newton
• What is the unit of Mass?


  Kilograms
• What is the unit of gravity?

  Meter per second squared
• What is the formula of weight?

  W=mg
• the two divisions of force

  Contact and non-contact
• This is the type of force where there is direct contact between the object

  Contact force
• This type of force acts on an object at a distance

  Non-contact force
• Under contact force this is when the object and surface are touching each other


  normal force
• Under contact force this is the resist and opposing movement between two surfaces in contact

  Frictional force
• Three types of frictional force

  Static sliding and rolling
• Refers to the force between two stationary surfaces in contact that prevents movement

  static friction
• Refers to the resistance of sliding objects

  Sliding friction
• Refers to resistance to motion experienced from rollers

  Rolling friction
• Under non-contact forces this when force is exerted by the planets in the solar system because of large mass

  Gravity
• this is a force under non contact forces that is present in particles with electrical charges

  Electromagnetism
• Under non contact forces that holds the positive protons and neutral neutrons in the atomic nucleus

  Strong force
• This is under non contact forces that is responsible for the decay of mater and is stringer than gravity.

  weak force
• The different types of weak force

  Alpha Beta Gamma