Forces

• A force is a push or pull that one object exerts on another through mutual interaction between the two or more objects.
• A force causes one or more of the following to changes:

  • Change in position
  • Change in dimensions
  • Change in shape
  • Change in speed
  • Change in direction
• The S.I unit for force is the newton (N).
• Forces are represented using arrows.
• The length of the arrow indicate the magnitude of the force.
• the arrow points in the direction of the force.
• Contact forces: These exist between objects that are in contact with each other.
• Non-contact forces: These exist between two objects separated from each other.
• Contact Forces

  • Frictional forces
  • Tension in strings, ropes, wires, springs
  • Normal reaction forces

  Elastic forces

  Expansion force of heated object

  Upthrust force on floating object
• Non-contact forces

  • Gravitational force
  • Magnetic force
  • Electrostatic force
  • Nuclear force
• Mass is the amount of matter in an object
• The inertia of matter is the tendency of matter to resist changes to its  motion.
• Gravitational forces are attractive forces that exist between bodies due to their masses.
• NORMAL REACTION FORCE: the backward push that a surfaces gives when it is pushed in the first place  by a body.
• weight is the gravitational pull on an object
• Weight = mass x gravity (W=mg)
• THRUST: the push exerted on a body by another body in contact with it.
• Tension: the pull force that can be exerted by a wire or cable
• Upthrust: the upward force that a body experiences when it floats in a fluid.
• friction: the force that act between two surfaces when one moves against the other
• static friction: a force or type of friction that keeps an object at rest
• kinetic friction: friction between two objects that are moving at different speeds
• electrostatic force: the force of attraction or repulsion between charged particles
• magnetic force: the force of attraction or repulsion between magnetic materials
• nuclear force: the force that acts between protons and neutrons in the nucleaus
• elastic force: a force in elastic materials that causes materials to stretch back into its original position after being stretched.