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forces - Coggle Diagram

- - - - the pressure exerted by the air in the atmosphere
    - - drinking straws
      - suction cups
- - - - hold on to objects
      - slow down or stop moving objects
      - moving across rough surfaces
    - - it opposes motion
      - it produces heat in machines
      - wear and tear
      - wastage of energy
    - - use lubricating oil or cold water
      - use ball bearings, rollers or wheels
      - use a cushion of air
  - - - high and low tides in harbours and coastal areas
    - - a measurement of the amount of gravitational force that acts on an object
  - - - unlike charges attract each other, the force acting on the positive and negative charges is called the electrostatic force of attraction
      - like charges repel each other. the force acting on the negative charges is called electrostatic force of repulsion
  - - - unlike poles attract each other, the force acting on the poles is called magnetic force of attraction
      - like poles repel each other, the force acting on the poles is the magnetic force of repulsion.
- - - - the spring in an extension spring balance stretches when a pulling force acts on it
    - - the spring in a compression spring balance is compressed when a pushing force acts on it
  - - - take g as gravitational field strength
    - - weight of a boy is 20kg. take g=10N/kg
        
        20 x 10 = 200
        ans: 200N
      - note : answers must be in S.I units form
    - - it is the amount of matter in an object (S.I unit- kilogram, kg)
    - - it is the amount of gravitational force acting on an object (S.I unit- newton, N)
    - - on earth: mass is 60kg, g is 10N/kg
        
        weight = 600N
      - on the moon: mass is 60kg, g is 10 divide 6 N/kg
        
        weight = 100N
    - - mass remains constant, regardless of location.
        weight changes due to the gravitational field strength at a location
      - mass is measured with beam balance and electronic balance. weight is measured with spring balance
  - - - it is the distance travelled per unit time
    - - m/s or km/h
- - - - whenever an object is touched, contact forces act on it
      - eg. frictional force, air resistance, tension
    - - a force that acts on an object without touching it
      - eg. gravitational force, electrostatic force, magnetic force