III. Force

• Force is the push/pull that causes change in the speed, direction of motion, and shape of an object
• Contact Forces occurs when two objects are in contact with each other.
• Contact forces is the result of the objects interacting with each other.
• Contact force includes normal force, frictional force, applied force, and tension force.
• Non-contact forces operate between objects without physical contact
• Non-contact forces include electrostatic force, gravitational force, and magnetic force.
• Spring balance is used to measure forces
• Concurrent forces are forces acting at one point
• Resultant force is combined effect of all forces applied
• Equilibrant force is the force equal to resultant but in different direction
• Friction is the resistance when one body is moved against another body
• Static is a type of friction from stationary surfaces
• Sliding is a type of friction from sliding surfaces
• Rolling is a type of friction from rollers
• Law of inertia states that net resultant force is equal to zero, and that the object will remain at rest or in motion unless acted upon by an external force
• Law of Acceleration states that the acceleration of an object is directly proportional to the net force acting on it.
• Law of acceleration:

  Force = mass x acceleration

  Weight = mass x 9.8 m's^2
• Law of action and reaction states that for every action there is an equal and opposite reaction.
• Law of action and reaction:

  F action = -F reaction
• Laws of Motion:

  • Law of Inertia
  • Law of Acceleration
  • Law of Action & Reaction