Phy Chap 3

• Contact Forces


  Contact forces occurs due to the contact between different bodies or objects;

  There is no field present due to contact forces

  -Friction

  -Air Resistance

  -Tension

  -Normal Force
• Non-contact Forces

  Non-contact forces occur due to either attraction or repulsion between two bodies / object where there is no contact between these bodies / objects;

  There is a field present due to non-contact forces.

  -Gravitational (Gravitational Field)

  -Electrostatic (Electric Field)

  -Magnetic(Magnetic Field)
• Mass

  Mass is defined as the amount of matter in an object / body ;

  kg ;

  Scalar quantity ;

  F=MA ;

  Mass is constant and is not affected by gravity ;

  Beam balance , Lever balance , Electronic Balance
• Weight

  Weight is a measure of the gravitational force acting on an object due to the gravitational field ;

  N ;

  Vector quantity ;

  W = mg ;

  Weight is dependent on the gravitational field ;

  Spring balance
• Human Reaction Time

  $x^2=$$2(average)/g$