Question 1: Define kinetic energy and explain how it depends on an object's mass and speed.

Answer: Kinetic energy is the energy an object possesses due to its motion. It depends on the object's mass and the square of its speed, following the formula KE = ½ m v².

Question 1: A car with a mass of 1500 kg is travelling at a speed of 20 m/s. Calculate its kinetic energy in joules.

Answer: KE = ½ × 1500 kg × (20 m/s)² = 0.5 × 1500 × 400 = 300,000 Joules

Question 2: A cyclist with a mass of 70 kg is moving at 10 m/s. What is their kinetic energy? (Show your working.)

Answer: KE = ½ × 70 kg × (10 m/s)² = 0.5 × 70 × 100 = 3,500 Joules

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

Answer: Students could measure the mass of the object and its speed using a motion sensor or timer and a measuring tape. Variables include mass, speed, and the type of surface. Safety precautions involve ensuring the area is clear of obstacles, wearing safety goggles if necessary, and handling moving objects carefully to avoid injury.

Question 2: Identify two real-world applications where understanding kinetic energy is crucial and explain why.

Answer: Kinetic energy is crucial in vehicle safety design, such as airbags and crumple zones, to absorb energy during collisions. It is also important in sports, like in analysing the motion of balls to improve performance.

Question 3: An object with a mass of 2 kg is moving at 5 m/s. If its speed doubles, what is its new kinetic energy? Explain your reasoning.

Answer: Original KE = ½ × 2 kg × (5 m/s)² = 0.5 × 2 × 25 = 25 Joules. If speed doubles to 10 m/s, new KE = ½ × 2 × (10)² = 0.5 × 2 × 100 = 100 Joules. The kinetic energy increases by a factor of four when the speed doubles.