Exam Questions - Power

Exam Questions - Power

Section 1: Understanding Power

  • Remember, Power is the rate of doing work or the rate of transfer of energy.
  • Understand that Power (P) can be calculated using the formula P = W/t, where W is work done and t is time taken.
  • Be aware that power can also be defined as the scalar product of force and velocity, i.e., P = Fv cosθ, where F is force, v is velocity and θ is the angle between the direction of force and velocity.

Section 2: Calculating Power

  • Review that when calculating power, if work or energy is given in Joules and time is given in seconds, the resulting unit of power is Watts (W).
  • In cases where force and velocity are used in the formula, force is measured in Newtons (N), velocity in meters per second (m/s), and power again is in Watts (W).
  • Keep in mind that if the motion of an object is in the same direction of the force applied on it, the value of cosθ becomes 1 and hence, power is simply the product of force and velocity.

Section 3: Application of Power in Different Contexts

  • Understand how to apply the concept of power in a variety of contexts such as calculating the power exerted during an uphill climb, jog or sprint.
  • Note that power retained by a machine or a mechanism is less than the power input due to energy losses primarily as heat due to friction.

Section 4: Solving Power Problems in Exams

  • Become skilled at using the definitions and formulas of power to solve examination problems.
  • Always start by identifying the known quantities in the question, and work step by step to reach the required unknowns.
  • Make sure all your answers are in correct units and double-check your calculations to avoid any arithmetic errors.

Section 5: Practice Exam Questions

  • Regularly solve practice questions related to Power to consolidate understanding and enhance application skills.
  • Work step-by-step and always verify the final solution against the resolution provided.
  • Continually revisit mistakes to avoid repeating them in the final exam, and working on improving speed without compromising accuracy.