Dynamics

• What are the main scalar quantities?

  • Distance
  • Length
  • Energy
  • Time
  • Speed
  • Mass
• What are the main vector quantities?

  • Displacement
  • Force
  • Acceleration
  • Velocity
• What is the formula for work done?

  Work done (Ew) = Force (F) × Distance (d)
• What factors can affect how much work is needed to move an object?

  • Resistance
  • Friction
  • Mass
• What is gravitational potential energy (Ep) formula?


  Ep = mass (m) × gravitational field strength (g) × height (h)
• What is the formula for kinetic energy (Ek)?


  Ek = 0.5 × mass (m) × velocity² (v²)
• If the velocity of an object doubles, how does its kinetic energy change?

  The kinetic energy quadruples
• What is the unit of power?

  Watts
• What is the relationship between power, energy, and time?

  Power (P) = Energy (E) / Time (t)
• What does Newton's Second Law state?


  F = ma (Force equals mass times acceleration)
• What is the formula for calculating work done (Ew)?

  Ew = Force (F) × Distance (d)
• What is the formula for gravitational potential energy (Ep)?


  Ep = mgh
• What is the relationship between kinetic energy and velocity?

  • Kinetic energy is proportional to the square of the velocity.
  • If velocity doubles, kinetic energy quadruples.
• What is the formula for kinetic energy (Ek)?


  Ek = 0.5 × m × v²
• What is the unit of energy?

  Joules
• What is the relationship between mass and kinetic energy?

  Kinetic energy increases with an increase in mass
• If the velocity of a toy doubles, how does its kinetic energy change?

  The kinetic energy quadruples
• What is the effect of increasing the number of bands on the velocity of a trolley?

  The velocity of the trolley increases as the number of bands increases
• How does the graph of kinetic energy versus velocity squared appear?

  It appears as a straight line
• What is the formula for calculating power?

  Power (P) = Energy (E) / Time (t)
• What is the formula for kinetic energy (KE)?


  KE = \frac{1}{2} mv^2
• What is the formula for potential energy (PE)?


  PE = mgh
• How does kinetic energy change as height increases?

  The kinetic energy increases as height increases.
• Why are the two energy values not exactly the same?

  Because of thermal energy, friction, or air resistance.
• At what height are the two energy values most similar?

  At a smaller height, due to less time for friction to act.
• What principle explains the relationship between potential energy and kinetic energy in the examples provided?

  Due to conservation of energy, potential energy converts to kinetic energy.
• What are the key concepts of conservation of energy?

  • Kinetic energy (KE) increases as potential energy (PE) decreases.
  • Energy is lost due to friction and air resistance.
  • The two energy values are most similar at lower heights.
• What are the steps to calculate the kinetic energy and velocity of a diver?


  1. Calculate potential energy using \( PE = mgh \).
  2. Set potential energy equal to kinetic energy \( PE = KE \).
  3. Solve for kinetic energy.
  4. Use \( KE = \frac{1}{2} mv^2 \) to find velocity.
• How do you calculate the kinetic energy of the cyclist and bike at point X?


  Kinetic energy is calculated using the formula $KE =$$\frac{1}{2} mv^2$
• Why would the actual height of the jump above point X be less than the calculated height?

  Because the equation did not take air resistance into account.
• What is the formula for kinetic energy?


  $KE =$$\frac{1}{2} mv^2$
• What happens to the kinetic energy of the car when it comes to a stop?

  It is converted into heat energy.
• How do you calculate the height of the cliff from which the student fell?

  Using the formula $h =$$\frac{1}{2} g t^2$
• What is a scalar?


  Has only magnitude (e.g 50m)
• What is a vector?

  Has magnitude and direction (e.g 50m to the East)
• When an object is lifted a force equal to the objects ..... must be used

  Weight
• In terms of Ep what happens to a falling object?

  It loses gravitational potential energy
• In terms of Ep, what happens to a rising object?

  Gains gravitational potential energy
• Describe how a projectile travels in terms of horizontal and vertical motion?

  Travels horizontally at a constant velocity.

  Travels vertically with a constant acceleration.
• What happens to gravitational potential energy when an object falls?

  It will gain kinetic energy.