New
New
Year 10
OCR
Higher

Velocity-time graphs: acceleration and distance travelled (a=(v-u)/t)

I can read information from velocity-time graphs and calculate acceleration and distance travelled.

New
New
Year 10
OCR
Higher

Velocity-time graphs: acceleration and distance travelled (a=(v-u)/t)

I can read information from velocity-time graphs and calculate acceleration and distance travelled.

Lesson details

Key learning points

  1. A velocity-time graph shows how velocity changes with time.
  2. Acceleration is equal to the gradient of a velocity-time graph.
  3. A falling line shows decreasing velocity called deceleration, which is a negative acceleration.
  4. The gradient of the line gives the instantaneous acceleration.
  5. The distance travelled is equal to the area under a velocity-time graph.

Common misconception

Pupils often consider time in the acceleration equation to be moment in time (perhaps read from a graph) rather than a change in time.

Label the value of t in the acceleration as a change of time rather than just time.

Keywords

  • Displacement-time graph - A displacement-time graph shows the displacement of an object over a period of time.

  • Velocity-time graph - A velocity-time graph shows the velocity of an object over a period of time.

  • Acceleration - The acceleration of an object is the rate of change of velocity. This is how much the velocity changes per second.

  • Deceleration - Deceleration is used to describe a change in velocity where the object slows down.

Emphasise use of the terms 'change in time' and 'change in velocity' throughout the lesson. Model acceleration and use video clips showing a range of changes in speed as examples.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Five yachts have a sailing race around the same course. Their completion times are shown. Starting with the fastest, put them in order of average speed.
1 - 1 hour 15 minutes
2 - 1 hour 19 minutes
3 - 1 hour 20 minutes
4 - 1 hour 28 minutes
5 - 1 hours 49 minutes
Q2.
Which word is used to describe an object which has a decreasing velocity?
Correct Answer: decelerating, deceleration
Q3.
An electric scooter has a maximum speed of 2.5 m/s. Calculate the maximum distance it can travel in 50 s.
2.5 m
20 m
47.5 m
52.5 m
Correct answer: 125 m
Q4.
A satellite travels a distance of 10 800 km in 1 hour. What is the speed of the satellite in km/s?
0.33 km/s
3.0 m/s
Correct answer: 3.0 km/s
180 km/s
10 800 km/s
Q5.
Which of these is the correct unit for acceleration?
m
m/s
Correct answer: m/s$$^2$$
m/s$$^3$$
Q6.
A train speeds up from 2.0 m/s to 8.0 m/s in a time of 50 s. Calculate the acceleration of the train.
0.04 m/s$$^2$$
Correct answer: 0.12 m/s$$^2$$
0.16 m/s$$^2$$
6.0 m/s$$^2$$
8.3 m/s$$^2$$

6 Questions

Q1.
Match the key words and phrases to their explanations.
Correct Answer:displacement-time graph,this shows the displacement of an object over a period of time

this shows the displacement of an object over a period of time

Correct Answer:velocity-time graph,this shows the velocity of an object over a period of time

this shows the velocity of an object over a period of time

Correct Answer:acceleration,the rate of change of velocity

the rate of change of velocity

Correct Answer:deceleration,used to describe an object which is slowing down

used to describe an object which is slowing down

Q2.
Find the change in velocity between 0 s and 8 s shown in this graph.
An image in a quiz
2 m/s
Correct answer: -2 m/s
6 m/s
-8 m/s
8 m/s
Q3.
When is the magnitude (size) of the acceleration greatest according to the velocity-time graph?
An image in a quiz
between 0 s and 2 s
between 2 s and 4 s
between 4 s and 5 s
Correct answer: between 5 s and 7 s
between 7 s and 8 s
Q4.
The graph shows an electric car with changing velocity. At which of these times is the acceleration greatest?
An image in a quiz
Correct answer: 1 s
2 s
3 s
4 s
8 s
Q5.
The displacement-time graph shows the movement of a robotic arm in a factory. Calculate the velocity of the arm in m/s between 0 s and 20 s. You do not need to provide the unit.
An image in a quiz
Correct Answer: 0.15, 0.15 metres per second, 0.15 m/s
Q6.
A car starts from rest and accelerates at a constant 3.5 m/s$$^2$$. Calculate its velocity after 6.0 s.
Correct Answer: 21 m/s, 21 metres per second