Starter quiz
Some swimmers compete in a 50m race. Their times are shown. Starting with the fastest, sort the swimmers in order of their speeds.- 1⇔29.9 s
- 2⇔30.2 s
- 3⇔31.1 s
- 4⇔31.2 s
- 5⇔31.4 s
- Which of the following are vector quantities?
- distance
- displacement ✓
- speed
- velocity ✓
- mass
-
- A rocket has a velocity of 200 m/s upwards. What distance will the rocket travel upwards in 30 s?
- 6.7 m
- 6000 m ✓
- 60 000 m
- 3000 m
- 600 m
-
- A jogger runs for 250 s and they end up 625 m west of their starting point. Calculate the average velocity of the jogger.
- 2.5 m/s west ✓
- 0.4 m/s west
- 375 m/s west
- 5.0 m/s west
-
- Two trains are travelling in the same direction. Train A has a speed of 6.5 m/s and train B has a speed of 5.5 m/s. What is the relative speed of the two trains?
- '1.0 m/s' ✓
An small airplane travels 45 km north in 30 minutes. Calculate the average velocity of the airplane in m/s.- 1.5 m/s north
- 22 m/s north
- 25 m/s north ✓
- 1500 m/s north
- 6.6 m/s north
-
Exit quiz
- Match the key word or phrase to the explanation.
- displacement⇔a vector which is the distance and direction from a point ✓
- velocity⇔a vector that gives speed and direction ✓
- displacement–time graph⇔shows the displacement of an object over a period of time ✓
- motion sensor⇔measures the distance between an object and itself ✓
- Which feature of a displacement-time graph shows the velocity?
- the intercept on the displacement axis (y-axis)
- the intercept on the displacement time (x-axis)
- the area beneath the line
- the gradient of the line ✓
- the maximum on the displacement axis
-
- An ultrasonic motion sensor is used to measure displacement of a ball. Put each step in order to explain how the sensor works.
- 1⇔the sensor sends out an ultrasound pulse
- 2⇔the sound pulse travels to the ball
- 3⇔the sound pulse reflects off the ball
- 4⇔the sound pulse travels to the sensor
- 5⇔the sensor detects the pulse
- 6⇔the speed of sound and the time information are used to calculate displacement
Which line on the graph show the highest velocity?- A (red)
- B (blue)
- C (black) ✓
- D (green)
-
Select the options which describe the motion between 1 s and 5 s.- positive displacement ✓
- positive velocity
- negative velocity ✓
- constant velocity ✓
- changing velocity
-
A pupil has plotted a graph to show their movement as they run across the classroom. Why is this graph unrealistic?- The change in their velocity is too sudden. ✓
- Their velocity is too high for a human to run.
- The velocity is too low for running.
- It does not take into account the direction of travel.
- They have not given the graph a title.
-
Worksheet
Loading worksheet ...
Presentation
Loading presentation ...
Video
Lesson Details
Key learning points
- The velocity of an object is equal to the gradient of a displacement-time graph.
- A direction in which velocity and displacement are measured needs to be chosen.
- A negative gradient on a displacement-time graph (sloping downwards) represents velocity in the opposite direction.
- A negative value for displacement represents a position ‘behind’ the starting position.
Common misconception
Negative values on a displacement-time graph always represent motion that is backwards.
Provide opportunities for pupils to plot a range of displacement-time graphs in real time in order for them to understand how the graph represents different motions.
Keywords
Displacement - The displacement of an object is the distance and direction from a specific point. Displacement is a vector.
Displacement-time graph - A displacement-time graph shows the displacement of an object over a period of time.
Motion sensor - A motion sensor measures the distance between itself and an object. We can use the measurements to calculate and plot graphs of displacement, velocity and acceleration.
+