Question 1: Explain in your own words what is meant by 'braking distance' and identify two factors that can influence it.

Answer: Braking distance is the distance a vehicle travels from the point where the driver applies the brakes until it comes to a complete stop. Factors influencing it include the initial speed of the vehicle and the road surface condition.

Question 1: Define 'deceleration' and describe its role in braking.

Answer: Deceleration is the rate at which an object slows down. In braking, it describes the reduction in the vehicle's speed due to the braking force applied.

Question 2: What is the main physical principle that explains how brakes slow down a vehicle?

Answer: Friction between the brake pads and the wheels converts kinetic energy into heat, reducing the vehicle's speed.

Question 1: A car travelling at 20 m/s decelerates at a rate of 5 m/s². Calculate the braking distance.

Answer: Braking distance s = v² / (2a) = (20)² / (2 × 5) = 400 / 10 = 40 metres

Question 2: If a vehicle's initial speed is 15 m/s and the braking distance is 22.5 metres, what is the constant deceleration assuming it remains uniform?

Answer: a = v² / (2s) = (15)² / (2 × 22.5) = 225 / 45 = 5 m/s²

Question 1: Describe a simple experiment to investigate how road surface affects braking distance. Include variables to be controlled and safety precautions.

Answer: An experiment could involve measuring the braking distance of a toy car on different surfaces such as smooth, wet, and rough. Controlled variables include the initial speed of the car and the mass. Safety precautions include ensuring the testing area is clear of obstacles and wearing protective gear if using larger vehicles.

Question 1: A vehicle travelling at 25 m/s takes 50 metres to come to a stop on a dry road. Assuming constant deceleration, calculate the deceleration of the vehicle.

Answer: a = v² / (2s) = (25)² / (2 × 50) = 625 / 100 = 6.25 m/s²

Question 1: Explain how understanding braking distances is important in designing safety features for autonomous vehicles.

Answer: Understanding braking distances helps engineers programme autonomous vehicles to react appropriately and stop within safe distances, reducing accidents. It informs the design of braking systems and sensors to ensure timely responses.

Question 2: Identify two technological advancements that have improved braking performance in modern vehicles.

Answer: Anti-lock braking systems (ABS) and electronic stability control (ESC) are two advancements that improve braking performance and vehicle stability.

Question 1: Derive the formula for braking distance starting from the equations of motion, assuming initial speed v and constant deceleration a.

Answer: Starting with v² = u² + 2as, where u = initial speed, v = final speed (0), rearranged to s = v² / (2a). Since v = 0 at the stop, the braking distance s = v² / (2a).