Physics - Forces and Motion

• Speed is how fast you are going.

  Velocity is how fast you are going in one direction.
• Average Speed Formula 



  Average Speed = Distance/Time
• Acceleration Formula



  Acceleration = Change In Velocity/Time Taken
• Final Velocity Formula


  v² = u² + 2as

  V = Final Speed

  U = Initial Speed

  A = Acceleration

  S = Distance
• Unit Of Acceleration


  M/S²
• Acceleration is how quickly velocity is changing, measured in metres per second squared (ms^2)
• Distance-Time Graphs

  A) Steady Speed

  B) Accelerating

  C) Stopped

  D) Deceleration

  
• Speed in distance-time graphs formula



  Speed = Gradient = Vertical/Horizontal
• Velocity-Time Graphs Acceleration Formula



  acceleration = gradient = vertical/horizontal
• Velocity Time Graph Labelling

  A) Accelerating

  B) steady

  C) Deceleration

  D) Area under curve = Distance Travelled

  
• Weight Formula


  Weight = Mass X Gravitational Field Strength
• What is Mass?


  Mass is the amount of "stuff" in something
• What is weight?


  Weight is the pull of gravity that pulls something towards the earth.
• What is the First Law of Motion?

  Balanced Forces mean no change in velocity
• What is the Second Law of Motion?

  A resultant force means acceleration
• Resultant Force Formula


  Force = Mass X Acceleration
• What is the Third Law of Motion?

  Reaction Forces

  • If object A exerts a force on object B then object B exerts an equal and opposite force on object A.
• What are Vector Qualities?

  Force, Velocity, Acceleration, Momentum
• What are Scalar Qualities?


  Mass, Temperature, Time, Length
• What is the difference between a Vector Quality and a Scalar Quality?

  A Vector Quality has Size and Direction.

  A Scalar Quality has Size only.
• Hooke's Law

  • The length of an unstretched metal wire is called its natural length.
  • If a metal wire is supported at the top and then a weight is attached to the bottom, It stretches. The weight pulls down with Force F, producing an equal and opposite force at the support.
  • Extension is the length of how much the wire stretches.
• What is Terminal Velocity?


  It is the fastest velocity that is attainable by an object as it falls.
• Terminal velocity occurs when the accelerating force is equal to the resisting force.
• The stopping distance of a car is the distance between the driver first spotting a hazard and when the car comes to a stop completely
• Stopping Distance Formula

  Stopping Distance = Thinking Distance + Braking Distance
• Thinking Distance (T) is the time taken from seeing a potential danger until applying the brakes. This depends on the speed of the vehicle and the reaction times of the driver.
• Braking Distance (B) is the time taken from applying the brakes until coming to a complete stop. This depends on the friction between the tyres and road surface.
• Braking Distance is the time taken from applying the brakes until the car comes to a complete stop.
• Momentum Formula

  Momentum = Mass X Velocity
• Units and what they are used for :

  • Kilogram = Mass
  • Meter = Distance
  • Meter/Second = Speed
  • Meter/Second Squared = Acceleration
  • Newton = Force
  • Newton/Kilogram = Acceleration
• Factors affecting vehicle stopping distance :

  • Speed
  • How heavy the car is
  • The grip of the tires
  • How good the brakes are
• Force Formula

  Force = Changes in Momentum (v-u) / time
• Moment Formula


  Moment(nm) = Force(n) X perpendicular distance between line of action and pivot(m)
• forces and directions

  A) thrust

  B) weight

  C) lift

  D) air resistance