science phys Y10

• Speed


  How fast an object is travelling. The distance travelled per unit of time
• Acceleration


  The change (increase or decrease) in speed per unit of time or the change in direction
• Force


  A push or pull. Measured in Newtons
• Inertia


  The tendency of an object to resist any change in its motion
• Mass


  The amount of matter in an object. Measure in kilograms
• Weight


  The force exerted on an object by the Earth due to gravity. Measured in Newtons
• Gravity


  The force of attraction by Earth on an object
• Displacement


  The distance between starting and finishing points
• Calculate speed, distance and time


  1. Speed = Distance/Time

  2. Distance = Speed x Time

  3. Time = Distance/Speed
• Acceleration


  • Change in speed and/or direction as a result of a net force
  • A measure of the rate at which speed changes
• Calculate the acceleration, initial and final velocities and or time travelled


  1. Acceleration = (final velocity - initial velocity) / time travelled

  2. Time travelled = (final velocity - initial velocity) / Acceleration

  3. Final velocity = (Acceleration x Time travelled) + initial velocity

  4. Initial velocity = Final velocity - (Acceleration x Time travelled)
• Balanced forces


  Forces that are equal in magnitude but are acting in opposite direction, making it so they cancel each other out creating no change in movement
• Unbalanced forces


  Forces that are unequal in magnitude and may or may not act in the same direction, causing a change in movement
• If the forces acting on an object is balanced the object either: Be at rest or stopped, Travelling at a constant speed, Travelling in a straight line or in the same direction
• If the forces acting on an object is unbalanced the object will either: Increase in speed (acceleration), Decrease in speed (deceleration), Change direction, Change shapes
• Newton's First Law of Motion (the Law of Inertia)


  Any object at rest or moving at a constant speed in a straight line, will continue to do so unless acted on by an unbalanced force
• Inertia


  • An object's tendency to resist any change in its motion
  • Closely linked with the object's mass. The greater mass of an object, the greater the amount of inertia it would have compared to an object with lesser mass
• Newton's Second Law of Motion


  The acceleration of an object is directly proportional to the external force applied and inversely proportional to its mass
• Calculate the force, mass or acceleration of an object


  1. Force = mass x acceleration

  2. Mass = force / acceleration

  3. Acceleration = Force / mass
• Calculate the weight, mass or acceleration due to gravity of an object


  1. Weight = mass x acceleration due to gravity of an object

  2. Mass = weight / acceleration due to gravity of an object

  3. Acceleration due to gravity of an object = weight / mass
• Weight is measured in Newtons because it's a force, therefore it is calculated the exact same as when calculating force
• Newton's Third Law of Motion


  • For every force, there is an equal and opposite force such that the net force is zero
  • When one object puts a force on another, the second object always exert an equal and opposite force back onto the first. These are called action and reaction force