Forces in action

• What is it called when a force causes an object to move?

  Work done
• One joule of work is done when a force of one newton causes a displacement of 1 metre. One Joule = 1 newton metre.
• What is the equation for work done?


  Work done= Force x Distance
• Work done to overcome what causes and increase in thermal energy?


  Friction
• An electric lift uses electrical energy to do work against gravity. What was this lead to an increase in?

  Gravitational potential energy
• What must happen to change the shape of an object?


  More than one force must be applied
• If the object retains its original shape after forces are removed, what is it?


  Elastically deformed
• If the object does not return its original shape after forces have been remove, what is it?


  Inelastically deformed
• The extension of an elastic object is what to the applied force?


  Proportional
• What does it mean once the limit of proportionality has been exceeded?

  -doubling the force will no longer exactly double the extension

  -The relationship becomes non-linear

  -A force extension graph will stop being a straight line
• What is the gradient of the linear section of a force extension graph called?

  Spring constant
• What is the equation that applies to the linear section of a force extension graph?

  Force = spring constant x extension
• What is spring constant (k) measured in?

  Newton per meter (N/m)
• What is the compression of an elastic object?

  Deformation
• What does the spring constant indicate?

  Stiffness
• A force that stretches or compresses, a string stores or elastic potential energy in the spring.
• What is the required practical for forces in action?

  Investigating the relationship between force and extension for a spring.