Physics

• What are the six key areas of the Dynamics topic in the National Fire Physics course?

  Vectors and scalars, acceleration, velocity time graphs, Newton's Laws, projectile motion, and energy
• What is the difference between vector and scalar quantities?

  • Scalar quantities have magnitude only.
  • Vector quantities have both magnitude and direction.
• Which quantities are considered scalar quantities?

  Speed, distance, mass, time, and energy
• Which quantities are considered vector quantities?

  Force, velocity, displacement, and acceleration
• How do you calculate the resultant of two vector quantities in one dimension?

  Add them tip to tail
• How do you calculate the resultant of two vector quantities at right angles?

  Draw a right angle triangle and use Pythagoras' theorem
• What is the purpose of a scale diagram in vector addition?

  To visually represent vectors and measure the resultant vector
• How do you find the hypotenuse of a right triangle using Pythagoras' theorem?

  $c^2 =$$a^2 +$$b^2$
• How do you find the angle in a right triangle using trigonometry?

  $\tan \theta =$$\frac{\text{opposite}}{\text{adjacent}}$
• What is the equation for displacement in terms of velocity and time?

  $s =$$vt$
• What is the equation for distance in terms of average speed and time?

  $D =$$\bar{V} t$
• What is the equation for displacement in terms of average velocity and time?

  $s =$$\bar{V} t$
• How do you measure average speed using light gates?

  By measuring the time taken for a card to pass through two light gates
• What is the formula for calculating average speed?

  $V =$$\frac{D}{T}$
• How is instantaneous speed measured using light gates?

  By measuring the time taken for the front and back of a card to pass through one light gate
• What is the definition of acceleration?

  Change in velocity per unit time
• What is the equation for acceleration?

  $a =$$\frac{V - U}{T}$
• How can you determine acceleration from a velocity-time graph?

  By calculating the gradient of the line on the graph
• What is the purpose of a velocity-time graph?

  To describe the motion of an object
• What does a straight horizontal line on a velocity-time graph represent?

  Constant velocity
• What does a positively sloping line on a velocity-time graph represent?

  Uniform or constant acceleration
• What does a negatively sloping line on a velocity-time graph represent?

  Constant deceleration
• How can you determine displacement from a velocity-time graph?

  By finding the area under the graph
• What is Newton's first law of motion about?

  Balanced forces and constant velocity
• How do you apply Newton's second law?

  By combining forces acting on an object
• What is the equation for Newton's second law?

  $F =$$ma$
• What is the equation for weight in terms of mass and gravitational field strength?

  $W =$$mg$
• What is the value of gravitational field strength on Earth?

  1. 9.8 N/kg
• What is the value of gravitational field strength on the Moon?

  1. 1.6 N/kg
• What is the value of gravitational field strength on Mars and Mercury?

  1. 3.7 N/kg
• What is Newton's third law of motion?

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

  When an object experiences the influence of gravity alone
• What is terminal velocity?

  When the forces acting on a falling object become balanced
• How does a skydiver experience free fall and terminal velocity?

  They accelerate downwards until air resistance balances their weight
• What is projectile motion?

  Motion involving constant vertical acceleration and constant horizontal velocity
• How do you find the horizontal distance traveled in projectile motion?

  By finding the area under the horizontal velocity-time graph
• How do you find the vertical distance traveled in projectile motion?

  By finding the area under the vertical velocity-time graph
• What is the relationship between horizontal velocity and time in projectile motion?

  $V_H =$$\frac{s}{T}$
• What is the equation for final vertical velocity in projectile motion?

  $V_V =$$U_V +$$at$
• How do satellites travel in circular orbits?

  By having a horizontal velocity that matches the Earth's curvature