Forces

• Vectors has magnitude and direction
• Vectors are : force, velocity, displacement, acceleration, momentum
• Scalar only had magnitude
• Scalars are: speed, distance, mass, temperature, time
• Magnitude is distance or quantity
• Contact forces are: friction, air resistance, tension, and normal contact force
• Non-contact forces are: magnetic force, gravitational force, electrostatic force, and nuclear force
• When two objects interact there is a force produced on BOTH objects
• Mass is the amount of stuff in the object and it will remain the same anywhere in the universe
• Weight is a force Acting on the object due to gravity
• Gravitational field strength varies within location. Earths is 9.8N/kg
• Weight= mass x gravitational field strength
• Mass and weight are directly proportional
• Resultant force is the overall force acting on a object
• If there is no resultant force, then the object is at rest or moving with constant velocity (no acceleration)
• If a resultant force moves work is done
• When a force moves an object through a distance energy is transferred and work is done on the object
• Work done = Force x Distance moved by object
• An object is at equilibrium if the forces are balanced
• An object has been elastically deformed if it can go back to its original shape and length
• Inelastic deformation is when it doesn’t return to its original shape and length after the force been removed
• Force = spring constant x extension
• Extension is directly proportional to the force
• Investigating Springs:

  1. measure the natural length of the spring when clamped to a stand
  2. add a mass to the spring and then allow it to rest before recording the new length
  3. repeat this process until You have enough measurements
• Elastic potential energy= 1/2 x spring constant x extension squared
• Energy transferred = Work done (J)
• A moment is the turning effect of a force
• Moment= Force x perpendicular distance from the pivot to the line of action of the force
• Levers increase the distance from the pivot at which the force is applied
• Different sized gears can be used to change the moment of a force
• The larger the gear the slower it will turn
• Pressure = force / area
• Pressure in a liquid depend on depth and density
• Pressure = height x density x gravitational field strength
• Objects in liquid experience up thrust
• When an object is submerged into a fluid the pressure of the fluid exerts a force on it in every directions
• Pressure increases within depth
• Up thrust is equal to the weight of an object
• An object floats if its weight= up thrust
• If an object upthrust and weight are equal the forces balances and the object floats