Displacement and velocity as vectors (v=x/t)
Lesson details
Learning outcome
I can represent and calculate the velocity of moving objects.
Key learning points
- The velocity of an object is its speed in a given direction.
- The displacement of an object is the distance it travels in a particular direction.
- Displacement and velocity are both vector quantities.
- Velocity has a positive value in one direction and negative value in the opposite direction.
Keywords
Displacement - The displacement of an object is the distance travelled in a particular direction from a starting point.
Vector - A vector is a quantity with magnitude (size) and direction. Displacement and velocity are both vector quantities.
Velocity - The velocity of an object is its speed in a particular direction.
Common misconception
Pupils often have a tendency to believe that a velocity must have a positive value and have difficulty in associating a reverse in direction with a change in sign.
It is important to make sure pupils are secure in their knowledge of the vector–scalar distinction; use plenty of visual examples.
Teacher tip
A common definition of velocity is ‘speed in a given direction’, but this is only true for instantaneous speed and velocity and very rarely true for average speed and velocity. This distinction is explained with examples in this lesson in the learning cycle 'average velocity'.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.A pupil measures the time taken for different sports balls to travel 30 cm.
Use the times to put the balls in order of decreasing speed, starting with the fastest.
Q2.Which three of these equations show the correct relationship between average speed, distance travelled and time taken?
Q3.What should be done with a single anomalous result in a set of five readings?
Q4.A pupil measures the time it takes for a car to pass between two street lamps as 5.0 s.
If the car is moving at 8.0 m/s, how far apart are the lamps?
Q5.Which of these is a correct definition of a scalar quantity?
Q6.A tennis ball was released from a height of 20 m and took 20 s to fall to the ground.
Which statements about the speed of the ball are correct?
Assessment exit quiz
6 Questions
Q1.Match the key words or phrases to their definitions.
the distance travelled in a straight line from a starting point
a quantity with a magnitude (size) and a direction
a quantity with a magnitude (size) but not a direction
the speed of an object in a particular direction
Q2.Which of these are examples of displacements?
Q3.A train takes 2 hours to travel from one station to another which is 150 km west of the starting point.
Calculate the velocity of the train.
Q4.A pupil walks 5 m north, 3 m south and then 2 m north.
Which of these statements about the pupil's journey are correct?
Q5.Two cars are approaching each other. Car A has a velocity of 4 m/s west and Car B has a velocity of 4 m/s east.
What is the relative velocity (speed) of the two cars?
Q6.A pupil walks 10 m west in 10 s, 5 m east in 5 s and 15 m west in 25 s.
Calculate the magnitude of the average velocity for the complete journey (do not give the direction).
To help you plan your 10 combined science lesson on: Displacement and velocity as vectors (v=x/t), download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 combined science lesson on: Displacement and velocity as vectors (v=x/t), download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 combined science lessons from the Measuring and calculating motion unit, dive into the full secondary combined science curriculum, or learn more about lesson planning.