forces

• What is a force and what can it do?

  A force is a push and pull. It is an action that changes or maintains the motion of a body or object.
• What is a contact force (give 2 examples)?

  A force that occurs when two objects are in contact (examples: friction, tension)
• What is a non-contact force (give 2 examples)?

  a force which acts on an object without coming physically in contact with it (examples: gravitational force, magnetic force)
• What is a spring balance/force meter?

  It is a tool for measuring the force exerted on an object. It is usually measured in Newtons.
• What unit is used to measure force?

  Newtons
• What's the difference between mass and weight.

  Mass stays the same whilst weight changes when the gravitational force changes.
• What is the formula used to calculate weight?

  weight = mass x gravitational pull
• What direction does friction work?

  It acts in the opposite direction of the applied force.
• Is friction bad?

  Friction isn't always bad. It is crucial for our day to day lives, without friction we wouldn't be able to walk without slipping.
• How can we minimise friction?

  We can minimise friction by adding wheels or lubricating (oil or grease) and polishing the surface.
• what is speed?

  The distance an object travels per unit of time
• what is the formula to calculate speed?

  speed = distance / time
• What is velocity?


  the speed of something in a given direction
• what is the equation to calculate velocity

  velocity = speed / time
• what is the difference between displacement and distance

  Distance is the length of the path taken by an object whereas displacement is the distance between where the object started and where it ended up.
• what is acceleration

  acceleration is the rate of change of velocity
• what is the formula for acceleration?

  acceleration = change in velocity / how long it took for the change to occur
• what is a scalar quantity

  A scalar quantity can be defined by its magnitude (or numerical value) but NO direction. An example is speed.
• What is a vector quantity

  A vector quantity is any quantity that has magnitude and direction. Such as displacement or velocity.
• Newton's 1st Law of Motion

  A body remains in the state of rest or uniform motion in a straight line unless and until an external force acts on it.
• Newton's 2nd Law of Motion

  The force acting on an object is equal to its mass times acceleration

  Force = mass of an object x acceleration
• Newton's 3rd Law of Motion

  Every action has an equal and opposite reaction