Question 1: Define kinetic energy and describe the factors that affect it.

Answer: Kinetic energy is the energy an object possesses due to its motion, affected by its mass and velocity.

Question 2: Explain why a heavier object moving at the same speed as a lighter one has more kinetic energy.

Answer: Because kinetic energy depends on mass, a heavier object has more energy when moving at the same speed.

Question 1: A car with a mass of 1500 kg is travelling at a speed of 20 m/s. Calculate its kinetic energy. (Use KE = 0.5 × m × v²)

Answer: 300,000 Joules

Question 2: A cyclist with a mass of 70 kg is moving at 10 m/s. What is her kinetic energy? (Use KE = 0.5 × m × v²)

Answer: 3,500 Joules

Question 1: Describe an experiment to measure the kinetic energy of a moving object. Include variables to control and safety precautions.

Answer: An experiment could involve measuring the mass and velocity of a moving object, such as a trolley on a ramp, using sensors. Variables to control include mass and initial velocity. Safety precautions include wearing safety goggles and ensuring the area is clear of obstacles.

Question 1: A train with a mass of 2 × 10^5 kg travels at 30 m/s. Another train of the same mass travels at 60 m/s. Compare their kinetic energies and explain the difference.

Answer: The first train's kinetic energy is KE1 = 0.5 × 200,000 kg × (30 m/s)^2 = 9 × 10^8 Joules. The second train's KE2 = 0.5 × 200,000 kg × (60 m/s)^2 = 3.6 × 10^9 Joules. The second train's kinetic energy is four times greater because KE depends on the square of velocity.

Question 2: A ball of mass 0.5 kg is dropped from a height of 10 meters. Ignoring air resistance, what is its kinetic energy just before hitting the ground? (Use gravitational potential energy formula: PE = mgh)

Answer: 2.45 Joules

Question 1: Explain how kinetic energy changes when the velocity of an object doubles. Include the relevant formula in your answer. (6 marks)

Answer: Kinetic energy is given by KE = 0.5 × m × v². When velocity doubles, v becomes 2v, and KE becomes 0.5 × m × (2v)² = 4 × 0.5 × m × v², which is four times the original KE. Thus, doubling the velocity increases the kinetic energy by a factor of four.

Question 1: Describe a practical example where kinetic energy is harnessed in industry or transportation, and explain its significance.

Answer: In car airbags, kinetic energy from a collision is absorbed or transformed to protect passengers. In transportation, kinetic energy of moving vehicles is used to generate electricity in regenerative braking systems, improving energy efficiency.