Physics 2 forces and motion

• Force


  A push or a pull
• Different forces


  • Force of gravity
  • Upthrust
  • Friction
  • Air resistance
  • Water resistance
  • Magnetism
• Force of gravity


  Massive things like planets have lots of this force
• Upthrust


  The force that makes objects float in fluids
• Friction


  The force between moving surfaces that tries to slow things down
• Air resistance


  The force that tries to slow things down when they move through the air
• Water resistance


  The force that tries to slow things down when they move through water
• Magnetism


  Attraction (pull towards) or repulsion (push away) of magnets and magnetic materials
• Non-contact force


  A force that can affect an object without touching it
• Contact force


  A force that has to touch the object before it has an effect
• Contact forces


  • Air resistance
  • Friction
  • Upthrust
  • Water resistance
  • Tension
• Non-contact forces


  • Gravity
  • Magnetic force
  • Static electricity
• Force


  Measured in newtons
• Balanced forces


  If an object is still or is moving at a constant speed, the forces are balanced
• Unbalanced forces


  If one of the forces acting on the object in one direction is bigger than those acting in the opposite direction, the forces are unbalanced
• Unbalanced forces


  Can cause an object to accelerate or decelerate depending on the direction of the overall force
• Resultant force


  The overall force acting on an object
• Calculating resultant force


  Take the smaller force away from the greater force, and the direction of the greater force is the direction in which the object travels
• Balanced forces


  If the forces on an object are equal in size but act in opposite directions
• Unbalanced forces


  If one force acting on an object is larger than another
• Unequal forces


  If one force acting on an object is larger than the other
• Resultant force acting on an object

  Can cause the object to accelerate or decelerate
• Resultant force acting on an object is zero


  The object will stay still
• Mass


  How much matter an object is made from, the bigger the mass the harder it is to move something
• Weight


  The force of gravity pulling on every kg of mass, the greater the force of gravity the bigger the weight on any given mass
• Weight


  Measured in newtons
• The Earth's gravitational pull is 10 N per kg
• 1 kg = 1000 grams
• 100 grams weigh 1 newton, 1 kg weighs 10 newtons
• Calculating weight


  Weight (N) = mass (kg) x gravitational field strength (N/kg)
• Pressure


  How spread out a force is over an area
• Calculating pressure


  Pressure = force / area
• As the area of an object increases

  The pressure decreases as there is a larger surface area for the pressure to be distributed upon