SCIENCE- FORCES AND MOTION

• Force


  The pull or push that you apply to an object causing it to move or stop moving and even change its direction
• Types of forces


  • Push
  • Pull
  • Twist
• Balanced forces


  Forces have the same value, so an object stays at rest
• Unbalanced forces


  Forces have different values, causing a change in speed or direction of an object
• Newton


  SI unit for force
• Motion


  Change in position with respect to time
• Types of motion


  • Change in speed
  • Change in direction
• Quantities with Direction and Size

  • Acceleration
  • Velocity
  • Momentum
  • Displacement

  
• Quantities with Size Only

  • Mass
  • Force
  • Temperature
  • Time
  • Speed
  • Energy
  • Length
  • Volume
• Scalar quantities


  Quantities that have magnitude or amount only, and direction is not important
• Vector quantities


  Quantities that have both magnitude and direction
• Examples of scalar quantities

  • Temperature
  • Mass
  • Time
  • Speed
  • Energy
  • Length
  • Volume
• Examples of vector quantities

  • Force
  • Acceleration
  • Velocity
  • Momentum
  • Displacement
• Contact forces


  Forces that must physically come in contact with an object or body in order to have an effect

  
• Examples of contact forces

  • Muscular force
  • Frictional force

  
• Non-contact forces


  Forces that can act upon objects without coming in contact with it
• Examples of non-contact forces

  • Gravitational force (gravity)
  • Magnetic force
  • Electrostatic force

  
• Unbalanced forces


  Forces required to cause a change in direction or movement of objects
• Balanced forces


  Forces that do not result in the change of an object's motion
• Frictional force


  Force that occurs as an object moves/slides across a surface, can result in sliding or static friction
• Frictional force


  • Sliding a book across a table
  • Rolling a ball on the ground
• Tension force


  Force acting on wires, string or ropes when pulled tightly by an object on the other end
• Normal force


  Force acting on an object that is in contact with a stable object, usually horizontally applied

  
• Normal force


  • Leaning against a wall
  • A box resting on a table
• Gravitational force


  Force acting upon objects from the Earth or moon which attracts objects to themselves
• Gravitational force is always equal to the weight of the object
• Weight


  Force = Mass x Gravity
• Calculating weight


  1. Weight (N) = Mass (kg) x Gravity

  2. Example: Weight of 75 kg person on Earth = 75 kg x 10 N/kg = 750 N
• Resultant force


  The overall force acting upon an object
• The force that acts on an object is called the resultant.
• A vector quantity has both magnitude (size) and direction, while a scalar quantity only has magnitude.
• To find the magnitude of the resultant force, add up the magnitudes of all the individual forces using vector addition.
• Vector quantities can be represented by arrows with length proportional to their magnitudes and directions indicated by arrowheads pointing towards the positive end of the axis.
• Forces can act at different angles from one another, resulting in a net force that is not equal to any individual force but rather a combination of all forces involved.
• Vector includes DIRECTION while scalar has none