Mechanics

• What is the difference between distance and displacement?


  Distance is a scalar quantity; displacement is a vector quantity.
• What does velocity represent in motion?


  Rate of change of displacement.
• What is uniform acceleration?


  Acceleration that is constant over time.
• What does the area under an acceleration-time graph represent?


  Change in velocity.

  
• What does the gradient of a velocity-time graph represent?


  Acceleration.

  
• How can instantaneous velocity be found from a displacement-time graph?


  By drawing a tangent and calculating the gradient.

  
• How is average velocity calculated?

  By dividing final displacement by time taken.
• What is the difference between scalars and vectors?


  Scalars have magnitude only; vectors have magnitude and direction.
• Give examples of scalar quantities.

  Distance, speed, mass, temperature.
• Give examples of vector quantities.

  Displacement, velocity, force, acceleration.
• How can vectors be represented in writing?


  As bold letters, underlined letters, or letters with an arrow above them.
• What does resolving a vector involve?


  Splitting a vector into its vertical and horizontal components.
• What is the purpose of a scale drawing in vector addition?


  To visually represent vectors and find the resultant vector.
• How do you find the resultant magnitude of two perpendicular vectors?


  Use Pythagoras’ theorem.
• How do you find the direction of the resultant vector?


  Use trigonometry to calculate the angle.
• What happens when two vectors are in the same direction?


  You can add or subtract their magnitudes directly.
• What is projectile motion?

  Motion where vertical and horizontal components are independent.
• How do you resolve the initial speed of a projectile into components?


  Use sine for vertical and cosine for horizontal components.
• What is the maximum height of a projectile?

  Occurs when the vertical component of velocity is zero.
• How do you find the time taken for a projectile to reach maximum height?


  Use the formula v = u + at.
• What is a free-body diagram?


  A diagram showing all forces acting on an object.

  
• What does Newton's first law state?

  An object remains at rest or in uniform motion unless acted upon by a resultant force.
• What does Newton's second law state?

  The acceleration of an object is proportional to the resultant force acting on it.
• How can you derive Newton's first law from the second law?


  By substituting a resultant force of 0 N into the second law.
• What is terminal velocity?

  When frictional forces equal driving forces, resulting in no acceleration.
• What is gravitational field strength?

  The force per unit mass exerted by a gravitational field on an object.
• What is weight?

  The gravitational force acting on an object due to its mass.
• What does Newton's third law state?

  For every action, there is an equal and opposite reaction.
• What is the significance of free-body diagrams?


  They show how forces compare with each other on an object.

  
• What is weight (W) in physics?

  Weight is the gravitational force acting on an object due to its mass.
• How is weight calculated?

  Weight is calculated by multiplying the object's mass by the gravitational field strength.
• What does Newton's second law state?


  Newton's second law states that force equals mass times acceleration (F = ma).
• How do you find the acceleration of an object using Newton's second law?


  Acceleration can be found using the formula a = F/m.
• What is momentum (p) in physics?


  Momentum is the product of the mass and velocity of an object.
• What does the principle of conservation of linear momentum state?


  The principle states that momentum is always conserved in interactions without external forces.
• How do you calculate the total momentum before a collision?


  Total momentum before a collision is the sum of the momenta of all objects involved.
• How can the principle of conservation of linear momentum be expressed mathematically for two colliding objects?


  p₁ + p₂ = 0, where p₁ and p₂ are the momenta of the two objects.
• What is the moment of a force about a point?


  The moment is the force multiplied by the perpendicular distance from the line of action to the point.
• What does the principle of moments state for an object in equilibrium?


  The sum of anticlockwise moments equals the sum of clockwise moments.
• How do you find the value of a force using the principle of moments?


  Set the sum of clockwise moments equal to the sum of anticlockwise moments.