Topic 2 - Motion and Forces

• What is a quantity in physics?

  A quantity is something that can be measured.
• What are the two types of quantities in physics?

  • Scalar Quantity: has magnitude (size)
  • Vector Quantity: has magnitude and direction
• Give an example of a scalar quantity.

  Speed
• Give an example of a vector quantity.

  Velocity
• What is the difference between distance and displacement?

  Distance is the range between two points, while displacement is the shortest distance between two points.
• Can scalar quantities be negative?

  No, scalar quantities can only be positive.
• Can vector quantities be negative?

  Yes, vector quantities can be positive or negative.
• What is speed defined as?

  Speed is the rate of change of distance.
• What is velocity defined as?

  Velocity is the rate of change of displacement.
• What is the formula for speed?

  Speed = distance / time
• What is the formula for velocity?

  Velocity = displacement / time
• What are the units for speed and velocity?

  Both are measured in meters per second (m/s).
• What does a distance-time graph indicate about an object's motion?

  • Straight line with positive gradient: Constant speed
  • Horizontal straight line: At rest
  • Curved line: Increasing speed
• What does the gradient of a distance-time graph represent?

  The gradient represents speed.
• What is acceleration defined as?

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

  Acceleration = change in velocity / time taken
• What are the units for acceleration?

  Acceleration is measured in meters per second squared (m/s²).
• What does a velocity-time graph indicate about an object's motion?

  A horizontal straight line indicates constant velocity, while a straight line with a positive gradient indicates increasing speed.
• What does the area under a velocity-time graph represent?

  The area under the graph represents the distance traveled.
• What is the formula for calculating uniform acceleration?

  Final velocity² = Initial velocity² + 2 × acceleration × distance
• What is the acceleration due to gravity?

  The acceleration due to gravity is approximately $10 \text{ m/s}^2$.
• What is the difference between mass and weight?

  Mass is the amount of matter in an object, while weight is the force of gravity acting on that object.
• What is the formula for weight?

  Weight = mass × gravitational field strength
• What are typical speeds for various activities?

  Walking: 1.4 m/s, Running: 3 m/s, Cycling: 4 m/s, Sound: 340 m/s, Wind: 5 m/s.
• What does Newton's First Law state?

  • A resultant force is needed to change the state of an object.
  • If the resultant force is zero, the object is either at rest or moving with constant speed.
• What is the normal contact force?

  The normal contact force acts at a right angle to the surface an object rests on.
• What does Newton's Second Law state?

  • Acceleration is proportional to the resultant force acting on an object.
  • Acceleration is inversely proportional to the object's mass.
• How does mass affect acceleration when force is constant?

  More mass results in less acceleration.
• How does air resistance affect velocity?

  As air resistance increases, velocity decreases.
• What happens when thrust equals air resistance?

  The resultant force acting is zero, indicating top speed.
• What is the relationship between force and acceleration?

  Force is proportional to acceleration when mass is constant.
• What is the relationship between mass and acceleration?

  Mass is inversely proportional to acceleration when force is constant.
• What happens to velocity as air resistance increases?

  Velocity decreases as air resistance increases.