1-3 (Forces and Newtons law of motion)

• Force


  The push and pull applied to an object, an influence that changes the motion of an object
• Applying force to an object

  1. Object remains stationary

  2. Apply force to move object

  3. Apply force in opposite direction to stop object
• Force


  • Magnitude (how strong the force is)
  • Direction (where the object goes)
  • Point of application (location where force is applied)
  • Line of action (straight line passing through point of application and parallel to direction of force)
• Magnitude of force


  Expressed in newton (mks system), dyne (cgs system), pound (fps system)
• The greater the magnitude of force, the faster the velocity of the object
• Types of force


  • Contact forces
  • Non-contact forces
• Contact forces


  • Applied force
  • Friction force
  • Normal force
  • Tension force
• Applied force


  Force exerted by a person or object towards another person or object
• Friction force


  Force that goes against the direction of the applied force, causing the object to slow down
• Normal force


  Upward force exerted by a surface on an object resting on it
• Tension force


  Force applied to a string, rope, chain, or cable, resisting the force that causes the object to stretch
• Gravity pulls objects towards the Earth, and the normal force supports the object and resists compression
• Non-contact forces


  Forces where objects do not touch or are not in contact with each other
• Examples of non-contact forces

  • Gravitational force
  • Magnetic force
• Gravitational force


  The force that attracts objects towards the earth
• Gravitational force is the main reason why we get to enjoy walking, running and living on earth</b>
• Without gravitational force, everything will float and many things would be very challenging to do
• Normal force


  The force that acts perpendicular to the surface which an object is in contact with
• The weight of an object is the gravitational force that pulls it downward
• Magnetic force


  The force that is exerted in a field of attraction or repulsion
• Magnets don't necessarily need to be in contact with other magnetic materials to make them move
• Balanced forces


  Forces which are of opposite directions and equal in magnitude
• Balanced forces result in no change in motion
• Unbalanced forces


  Forces which are in opposite direction and unequal in magnitude
• Unbalanced forces result in a change of motion and velocity
• Net force/Resultant force


  The sum of all the forces that act on an object
• If the net force is zero, the forces are balanced and there is no change in movement or velocity
• If the net force is greater than zero, there is a change in motion and velocity of the object
• Solving net force


  1. Use the formula: net force = sum of all forces

  2. Use positive and negative signs to indicate direction of forces
• Forces can only be added if they are in the same line of action
• The net force is the algebraic sum of all the forces acting on an object
• Experiences of riding a car

  • Car exhilarates abruptly, making you feel as if your body is pulled to the back
  • Driver suddenly steps on the brakes, and you feel the seat belt tighten
• Newton's first law of motion

  The law of inertia, which explains how an object responds to changes in motion
• Force


  Any push or pull that causes changes in the motion of an object
• Types of force


  • Contact force
  • Non-contact force
• Contact force


  Present when two or more surfaces or media touch and interact
• Friction


  A specific type of contact force, the object's resistance to motion
• Non-contact force


  Constantly present in nature and does not need human intervention to arise
• Non-contact force


  • The sun and planets exerting a gravitational pull on each other despite their large spatial separation
• Aspects of motion


  • Speed
  • Velocity
  • Acceleration