Read acceleration from the gradient and distance from the area under a velocity–time graph, including estimates for curves. It is Higher only, aimed at grade 8. Free questions with answers are on this page. Worked examples show each line before you try the questions.
On a velocity–time graph, gradient is acceleration and area under the line is displacement (distance travelled if the graph stays positive). A horizontal section is constant speed. A straight slope is constant acceleration. Below the time axis is reverse direction — areas then subtract if displacement from the start is asked, but add if total distance is asked.
Estimate a curved graph's area with trapezia. Units: velocity in m/s, time in s, area in metres, gradient in m/s². Do not read a v–t graph as if it were distance–time (a common mix-up after revising both).
Gradient is acceleration (including deceleration as negative). Area under the graph is displacement. A tangent at a point on a curve estimates instantaneous acceleration. Convert units if the axes are not in m and s.
Objectives
Read acceleration from a gradient.
Find distance as the area under the graph.
Use a trapezium when both speeds are non-zero.
Key points
Interpret each section of a velocity–time graph: speeding up, constant velocity, slowing down, stationary.
Calculate acceleration as the gradient, with units m/s².
Calculate distance as the area under the graph, splitting it into rectangles, triangles and trapezia.
Estimate the area under a curve using strips (trapezia) and say whether the estimate is too big or too small.
Worked examples
Example 1
A velocity-time graph is a straight line from 0 m/s to 8 m/s over 6 seconds. Find the distance.
2 marks
The shape is a triangle
Area = 1/2 times 6 times 8
24
Answer: 24
Common slips
Slip: The shape is a rectangle of height 8 It starts at rest, so one end has height 0.
Slip: Area = 6 times 8 A triangle is half the rectangle.
Slip: 48 Half of 48 is 24.
Example 2
Velocity goes from 4 m/s to 10 m/s in 5 seconds, in a straight line. Find the distance.
2 marks
Both ends are above zero, so use a trapezium
Average speed 7, times 5
35
Answer: 35
Common slips
Slip: Use a triangle of height 10 The starting speed is not zero.
Slip: Average speed 10 (4+10)/2 = 7.
Slip: 50 7 times 5 is 35.
Example 3
A cyclist holds 5 m/s for 4 seconds, then speeds up steadily to 9 m/s over the next 2 seconds. Find the distance.
3 marks
First piece is a rectangle 5 by 4
Second piece is a trapezium of heights 5 and 9 over 2 seconds
20 + 14 = 34
Answer: 34
Common slips
Slip: First piece is a triangle The speed is constant, so the area is a rectangle.
Slip: Second piece is 9 times 2 The speed does not jump to 9 at the start of that piece.
Slip: 20 + 18 = 38 Average of 5 and 9 is 7, times 2 is 14.
Questions and answers
GCSE Maths velocity–time graphs questions and answers. Try each one, then open the answer. Easy questions come first.
Question 1 Easy2 marks
From rest to 6 m/s in 10 seconds, in a straight line. What distance is travelled?
Show answer
Answer: 30
Triangle area.
Half of 10 times 6.
M1 — Triangle area.
A1 — Answer 30
Question 2 Easy2 marks
A constant velocity of 7 m/s is held for 3 seconds. What is the distance?
Show answer
Answer: 21
The graph is a rectangle.
7 times 3.
M1 — The graph is a rectangle.
A1 — Answer 21
Question 3 Medium2 marks
From 3 m/s to 7 m/s in 8 seconds, steadily. Find the distance.
Show answer
Answer: 40
Average of 3 and 7.
Times 8.
M1 — Average of 3 and 7.
A1 — Answer 40
Question 4 Medium2 marks
From 4 m/s to 10 m/s in 5 seconds. Find the acceleration.
Show answer
Answer: 1.2
Change is 6.
6 divided by 5.
M1 — Change is 6.
A1 — Answer 1.2
Question 5 Hard2 marks
6 m/s for 3 seconds, then a steady rise to 10 m/s over 4 more seconds. Find the total distance.
Show answer
Answer: 50
Rectangle 6 by 3.
Then a trapezium from 6 to 10 over 4 seconds.
M1 — Rectangle 6 by 3.
A1 — Answer 50
Question 6 Hard2 marks
The acceleration is 2 m/s^2 from rest. What velocity is reached after 5 seconds?
Show answer
Answer: 10
Velocity change = acceleration times time.
2 times 5.
M1 — Velocity change = acceleration times time.
A1 — Answer 10
Question 7 Exam-style5 marks
A runner travels at 4 m/s for 5 seconds, then slows steadily to rest over 5 more seconds. Find the total distance.
Show answer
Answer: 30
First area 4 times 5 = 20.
Second area is a triangle, half of 5 times 4.
That triangle is 10.
Total 30.
Rest means the second shape ends at height 0.
M1 — Rectangle
A1 — 20
M1 — Triangle
A1 — 10
A1 — Total 30
Common mistakes
Most lost marks on this topic are one slip.
Using the final speed as the distance
Distance is the area under the graph, not the last reading
Forgetting the half for a triangle or the average for a trapezium
Use half times base times height, or the average of the two speeds times the time
Dropping the minus sign when the speed falls
A falling line has a negative gradient, so the acceleration is negative
Spot the slip
A graph goes from 0 m/s to 8 m/s in a straight line. A student says the distance is 8. What did they forget?
The area, not the final speed
The gradient is the distance
Time cannot be read from the axis
Show the slip
The area, not the final speed Distance is the area of the triangle, half times base times height.
Exam tips
A calculator is useful here. Show the calculation you typed, not only the final line.
If the question says “show that”, the result is given. The marks are for the steps that reach it.
The method is the same on AQA-style and Edexcel-style papers.
Label each section of the graph with its shape (triangle, rectangle, trapezium) and write its area next to it — each area is usually a mark.
For an estimate question, state the number of strips you used and show every trapezium calculation.
Printable worksheet
The same questions are in a PDF you can print. Answers start on a later page.