Exam Questions - Work Energy Principle

Exam Questions - Work Energy Principle

Section 1: Understanding the Work Energy Principle

  • Grasp that the Work Energy Principle states that the work done on an object is equivalent to the change in its kinetic energy.
  • Recognise that work is done when a force acts upon an object to displace it, and this is given by the formula W = Fs, where F is the force and s is displacement.
  • Remember that kinetic energy (KE) can be defined as energy an object possesses due to its movement, and is given by the formula KE = ½mv², where m is mass and v is velocity.

Section 2: Calculating Work Done

  • Understand how to calculate work done by using the formula W = Fs cosθ, where θ is the angle between the force and the direction of displacement.
  • Learn to compute work done when the forces are not along the direction of displacement using vectors.
  • Note that if the movement is opposite to the direction of force, work done is negative and kinetic energy decreases.

Section 3: Work Done and Conservation of Energy

  • Understand that energy is always conserved and cannot be created or destroyed, which is a principle referred to as the conservation of energy.
  • Grasp that the change in an object’s kinetic energy is equal to the work done on it, which is another way of expressing the conservation of energy.

Section 4: Applying the Work Energy Principle to Exam Questions

  • Use the Work Energy principle to solve examination questions relating to the calculation of work done. This can help in understanding the behaviour of moving objects.
  • Approach problems by first identifying all the forces acting on an object and the displacement it undergoes.
  • Make sure to apply the principle correctly in various situations, such as when more than one force acts on an object, or when the forces are not constant.

Section 5: Practice Exam Questions

  • Solve numerous practice questions on this concept to reinforce understanding and gain proficiency in applying the Work Energy Principle.
  • Use diagrams to better visualise the situation and support the mental process of solving the question.
  • Review solutions for past questions to understand common pitfalls and improve problem-solving skills.