Question 1: Define kinetic energy and state the formula used to calculate it.

Answer: Kinetic energy is the energy possessed by a moving object. The formula is KE = 0.5 × mass × velocity^2.

Question 2: Explain how the velocity of an object affects its kinetic energy.

Answer: Kinetic energy increases with the square of the velocity, so doubling the velocity increases KE by a factor of four.

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

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

Question 2: A cyclist with a mass of 70 kg is travelling at 8 m/s. What is the kinetic energy of the cyclist?

Answer: KE = 0.5 × 70 kg × (8 m/s)^2 = 0.5 × 70 × 64 = 2240 Joules

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

Answer: A possible experiment involves measuring the velocity of a rolling ball down an inclined plane of known length and mass. Variables to control include the angle of the incline and the mass of the ball. Safety precautions include ensuring the area is clear of obstacles and wearing protective eyewear if necessary.

Question 2: Identify at least two factors that could affect the accuracy of kinetic energy measurements in a practical scenario.

Answer: Factors include measurement errors in velocity or mass, and energy losses due to friction or air resistance.

Question 1: A skateboarder decreases their speed from 10 m/s to 4 m/s. If their mass is 60 kg, calculate the change in kinetic energy.

Answer: Initial KE = 0.5 × 60 kg × (10)^2 = 0.5 × 60 × 100 = 3000 Joules. Final KE = 0.5 × 60 kg × (4)^2 = 0.5 × 60 × 16 = 480 Joules. Change in KE = 3000 - 480 = 2520 Joules.

Question 1: Explain how kinetic energy is utilised in the design of roller coasters to ensure safety and thrill.

Answer: Kinetic energy is maximised at the lowest point of the track to provide speed and excitement, while safety features like harnesses and brakes control the energy during descent and ascent to prevent accidents.

Question 2: Discuss the importance of kinetic energy in vehicle safety features such as crumple zones and airbags.

Answer: Kinetic energy during a collision is absorbed by crumple zones and airbags to reduce the force transmitted to passengers, protecting them from injury.