Question 1:

Shape of the graph:

1. First part (reaction time / thinking distance) –
   A horizontal straight line at constant velocity.

   • The driver sees the dog but hasn't yet applied the brakes.

   • Speed remains constant during the reaction time (typically 0.5–1.0 seconds).

2. Second part (braking phase) –
   A straight line sloping downwards to zero velocity.

   • Once brakes are applied, the bus decelerates uniformly (constant deceleration) until it stops.

   • The slope is negative and constant (assuming uniform braking).

   • The line ends on the time axis (velocity = 0) when the bus stops.

Summary:
→ Horizontal line (constant speed)
→ then straight line down to zero (constant deceleration)

This produces a two-part linear graph:

• Flat section = reaction time

• Slanted downward section = braking time

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 2:

Typical human reaction time

• For a simple visual stimulus (like seeing a dog run into the road), the average reaction time for an alert driver is about 0.2 to 0.3 seconds.

• This is the time it takes for:

  1. Light from the event to reach the eyes

  2. Signals to travel to the brain

  3. The brain to process the information

  4. Signals to travel to the foot/leg

  5. The foot to start moving toward the brake pedal

Why 0.3 s is reasonable

• 0.03 s (30 milliseconds) is far too fast — that's closer to the reaction time of a professional drag racer using a special "pro tree" light, not a normal driver in traffic.

• 0.3 s (300 milliseconds) is a commonly cited average for a healthy, alert person responding to an unexpected visual event.

Why not the other options?

• A. 0.03 s → unrealistic for normal driving (only possible with anticipation or very specialized training/equipment)

• C. 1.5 s → very slow; would represent a distracted, tired, or impaired driver

• D. 3 s → dangerously slow, not typical for an alert driver

  Final answer: B: 0.3 s

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 3:

The correct answer is:

C. Total stopping distance = thinking distance + braking distance

Explanation:

• Thinking distance = distance travelled during the driver's reaction time (constant speed)

• Braking distance = distance travelled while the brakes are applied (decelerating to stop)

• Total stopping distance = thinking distance + braking distance

The other options (×, –, ÷) do not correctly represent how these two distances combine.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 4:

The correct answer is:

B. Calculate the area under the line.

Explanation:
On a velocity–time graph, the distance travelled is found by calculating the area under the graph.

For this emergency stop:

• The area under the line represents the total stopping distance (thinking distance + braking distance).

• This area can be split into:

  • A rectangle (thinking distance: constant speed × reaction time)

  • A triangle (braking distance: ½ × base × height)

The other options:

• A → Not a standard formula; "maximum speed × time to stop" would overestimate distance unless acceleration were constant from the start (here, part of the time is at constant speed).

• C → Time to stop alone doesn't give distance.

• D → Gradient gives acceleration/deceleration, not distance.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 5:

Let's calculate the thinking distance from the graph details.

Graph details :

• Initial constant velocity = 12 m/s

• Reaction time (constant velocity) = 2 seconds

• Then brakes applied, velocity decreases to zero over next 2 seconds

Thinking distance = distance travelled during reaction time (constant speed)

Thinking distance=speed×reaction time

Thinking distance=12 m/s×2 s=24 m

The correct answer is B. 24 m.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 6:

• Braking time = 2 seconds (from t = 2 s to t = 4 s)

• Deceleration is uniform (straight line sloping down to zero)

Braking distance = area under the velocity–time graph during braking only (triangle)

For a triangle:

Here:

• Base (time) = 2 s

• Height (velocity) = 12 m/s

The correct answer is A. 12 m.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 7:

We already calculated:

• Thinking distance = 24 m

• Braking distance = 12 m

Total stopping distance = thinking distance + braking distance

The correct answer is C. 36 m.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 8:

We can calculate deceleration (negative acceleration) during the braking phase.

Given:

• Initial velocity (at start of braking) = 12 m/s

• Final velocity = 0 m/s

• Braking time = 2 s

a=(v−u)/t

a=(0−12)/2=−12/2=−6 m/s² (negative acceleration because it is decelerating).

The deceleration (magnitude) is 6 m/s².

The correct answer is D. 6 m/s².

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 9:

The correct answer is B. the driver having drunk alcohol.

Explanation:
Reaction time is affected by the driver's physical and mental state, including:

• Alcohol consumption

• Fatigue

• Distractions (e.g., mobile phone)

• Age or illness

The other options affect braking distance, not reaction time:

• A. Condition of the brakes → affects braking distance (how quickly the vehicle can decelerate)

• C. High speed of the vehicle → increases both thinking distance and braking distance, but does not increase reaction time itself

• D. High mass of the vehicle → affects braking distance (more mass = more force needed to decelerate), but not reaction time

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.

Question 10:

The correct answer is:

C. The driver taking drugs such as cough mixtures.

Explanation:
Braking distance is affected by factors that influence how effectively the vehicle can decelerate once the brakes are applied.

• A. Water on the road → affects braking distance (reduces friction between tyres and road)

• B. The speed of the truck → affects braking distance (higher speed = longer braking distance)

• D. The condition of the tyres → affects braking distance (worn or underinflated tyres reduce grip)

C. The driver taking drugs → affects reaction time (thinking distance), not braking distance. Once the brakes are applied, the vehicle's deceleration depends on mechanical and road factors, not the driver's state.

*These A.I. responses have been individually checked to ensure they match the accepted answer, but explanations may still be incorrect. Responses may give guidance but the A.I. might not be able to answer the question! This is particularly the case for questions based on diagrams, which the A.I. typically cannot interpret.
Grade Gorilla uses Gemini, Deepseek and a range of other A.I. chatbots to generate the saved responses. Some answers have had human intervention for clarity or where the A.I. has not been able to answer the question.