P1 - Motion and Forces

• What is the difference between speed and velocity?

  Speed is a measure of how far you travel in an amount of time.

  Velocity is how far you travel in a certain direction in an amount of time
• What is acceleration?

  Acceleration is the rate of change of velocity
• What is the equation for acceleration?

  Acceleration = change in velocity/time taken
• What is Newton's first law?

  An object at rest will remain at rest, and an object in motion will remain in motion with a constant velocity, unless acted upon by an external force
• What is Newton's second law?


  The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass
• What is equation for force?

  Force = mass x acceleration
• What is Newton's third law?

  For every action, there is an equal and opposite reaction
• What is weight?

  Weight is the force exerted on an object due to gravity
• What is the equation for weight?

  Weight = mass x gravitational field strength
• What is the difference between mass and weight?

  Mass is the amount of matter in an object, while weight is the force exerted on an object due to gravity
• What is the difference between balanced and unbalanced forces?

  Balanced forces result in no change in motion, while unbalanced forces result in a change in motion
• What is friction?

  Friction is a force that opposes motion between two surfaces in contact
• What is air resistance?

  A type of frictional force that opposes the motion of objects through air
• What is terminal velocity?

  The maximum velocity reached by a falling object when the upward force of air resistance is equal to the downward force of gravity
• What is momentum?

  The product of an object's mass and velocity
• What is the equation for momentum?

  Momentum = mass x velocity
• How do we calculate stopping distance?

  Stopping distance = thinking distance + braking distance
• What are the factors that can change thinking distance?

  Speed of car, age of driver, tiredness, influence of drugs or alcohol
• What are the factors that can change braking distance?

  Speed of car, age of tires, standard of brakes, road surface
• What are 3 car safety features and how do they work?

  Seat belt, air bag and crumple zones.

  Each one increases the time and therefore reduces the force on the passengers.