Question 1: Define work done in the context of physics.

Answer: Work done is the transfer of energy when a force is applied to an object and the object moves in the direction of the force.

Question 2: Explain why the angle between the force and displacement affects the work done.

Answer: Because work done depends on the component of the force in the direction of displacement, which is F × d × cos(θ).

Question 1: What is the SI unit of work done?

Answer: Joule (J)

Question 2: Describe a scenario where work is done but no energy transfer occurs.

Answer: If a force is applied but there is no displacement, then no work is done or energy is transferred.

Question 1: A person pushes a box with a force of 50 N over a distance of 4 m in the same direction as the force. Calculate the work done.

Answer: Work done = 50 N × 4 m × cos(0°) = 200 Joules

Question 2: A crane lifts a load vertically upwards with a force of 3000 N over a height of 10 m. What is the work done?

Answer: Work done = 3000 N × 10 m × cos(0°) = 30,000 Joules

Question 1: Describe a simple experiment to measure the work done when pushing an object across a surface.

Answer: Use a force sensor to measure the force applied while pushing an object over a known distance on a flat surface. Record the force and distance, then calculate work done using W = F × d.

Question 2: Identify three variables that could affect the accuracy of measuring work done in an experiment.

Answer: Force measurement accuracy, surface friction, and measurement of distance.

Question 1: A car accelerates from rest over a distance of 200 m, applying a constant force. Explain how work done relates to the car’s increase in kinetic energy.

Answer: The work done on the car equals its change in kinetic energy, according to the work-energy theorem. As force is applied over a distance, energy is transferred to the car, increasing its speed.

Question 2: In a scenario where a force is applied at an angle to the displacement, explain how to calculate the work done.

Answer: Calculate work done using W = F × d × cos(θ), where θ is the angle between the force and displacement.

Question 1: Explain how understanding work done is important in designing energy-efficient vehicles.

Answer: Designing energy-efficient vehicles involves minimising unnecessary work against factors like friction and air resistance, thereby reducing energy transfer and improving fuel efficiency.

Question 2: Identify a real-world device or machine where work done is a key consideration and briefly explain its importance.

Answer: Electric motors convert electrical energy into mechanical work; understanding work done helps optimise their efficiency and performance.