Forces

• What can forces be measured in?

  A newtonmeter
• What are contact forces?


  Forces that occur when things are touching
• What are non-contact forces?

  Forces that work at a distance
• What to forces always occur in?

  Pairs
• What are the pairs called?

  Interaction pairs
• When balanecd forces cancel out what is the object in?

  Equilibrium
• What is friction?


  Friction is the force that opposes the motion of an object when it comes into contact with another object or surface.
• What are water and air resistance?

  Drag forces
• How can friction be reduced?

  Lubrication
• How can you reduce the drag force on an object?


  Streamlining
• What is a support force that balances the weight of an object called?

  Reaction force
• What is a field in physics?

  Field is a special region where certain objects experience a non-contact force
• What is mass?


  The amount of 'stuff' something is made of
• What is mass measured in?

  kilograms
• What is weight measured in?

  Newtons
• What is the equation for weight?

  Weight = mass x gravitational field strength
• What is Hookes Law?

  The extension of a string doubles when you double the force
• What is moment?


  The moment is the turning effect of a force about a point.
• What is the equation for speed?

  Speed = Distance / Time
• What is speed measured in?

  Speed is measured in meters per second (m/s) or kilometers per hour (km/h).
• How do you calculate the moment?

  Force x Distance from pivot