Question 1: Define reaction time and explain its significance in vehicle braking safety.

Answer: Reaction time is the interval between perceiving a hazard and initiating an appropriate response. It is crucial in vehicle braking as it affects the total stopping distance and accident risk.

Question 2: Describe two factors that can influence a person's reaction time.

Answer: Factors include alertness level, age, fatigue, alcohol consumption, and distraction.

Question 3: In forensic investigations, why is reaction time important when analysing vehicle accidents?

Answer: Reaction time helps estimate the driver's response delay, which is critical in reconstructing the sequence of events and determining the cause of the accident.

Question 1: A car travelling at 20 m/s takes 4 seconds to come to a complete stop after the driver applies the brakes. Assuming the braking distance is 80 metres, calculate the reaction time of the driver. Use the formula: Total stopping distance = reaction distance + braking distance. Reaction distance = reaction time × speed.

Answer: Reaction time = (Total stopping distance - braking distance) / speed = (80 m - (20 m/s × 4 s)) / 20 m/s = (80 - 80) / 20 = 0 seconds (indicating reaction time is negligible in this case).

Question 2: A forensic scientist records a reaction time of 0.75 seconds for a driver involved in a collision. If the vehicle's initial speed was 25 m/s, what was the reaction distance? Use the formula: Reaction distance = reaction time × speed.

Answer: Reaction distance = 0.75 s × 25 m/s = 18.75 metres.

Question 1: Outline a simple experimental procedure to measure the reaction time of a person using a ruler. Include safety precautions and key variables to control.

Answer: The experiment involves the participant sitting with an outstretched hand aligned with a ruler held vertically. The ruler is dropped without warning, and the participant catches it as quickly as possible. The distance fallen is recorded, and reaction time is calculated using the formula: reaction time = √(2 × distance / acceleration due to gravity). Variables to control include the participant's posture, the initial position of the hand, and ensuring no prior distraction. Safety precautions involve explaining the procedure clearly to prevent injury and ensuring the participant's hand is stable.

Question 1: A forensic report states that a driver’s reaction time was estimated at 0.65 seconds based on skid marks and vehicle data. If the initial speed was 30 m/s, what was the reaction distance? How might this information be used in court?

Answer: Reaction distance = 0.65 s × 30 m/s = 19.5 metres. This information can help reconstruct the accident timeline, estimate the driver’s response delay, and determine liability.

Question 2: Discuss how technology such as driver alertness systems could reduce reaction times and improve safety in vehicles.

Answer: Driver alertness systems monitor signs of drowsiness or distraction, alerting the driver or taking corrective action. By reducing reaction times, these systems can decrease stopping distances, prevent accidents, and enhance overall road safety.