A measurement is repeatable if the same (or similar) results are obtained when the same person repeats the investigation using the same method.

A measurement is reproducible if the same (or similar) results are obtained when the same person repeats it using a different method, or a different person repeats it using the same method.

The instantaneous speed of an object is its speed at a particular moment in time.

If two variables are directly proportional, when one variable increases, the other increases at the same rate.

Measuring instantaneous speed analysis (v=s/t)

Combined science

In the Energy of moving objects unit, they will build on this knowledge to learn how to calculate the amount of energy of objects have because they are moving, stretched or in a gravitational field; and to calculate energy transfers using knowledge of energy conservation and dissipation.

In the Moving by force unit, pupils learnt how to calculate speed and describe motion using distance-time graphs, apply Newton’s First Law of motion and calculate the amount of energy needed to move an object to a new position.

Measuring and calculating motion

Physical activity and equipment requiring safe use

when the same results can be achieved by the same person and method

when the same results can be achieved by a different person or method

when one variable is a constant multiple of the other

Match the key word or phrase to the explanation.

Plot a graph to see if there is a relationship between variables.

Collect another set of results to compare with the first.

Have another person follow the same method and compare their results with yours.

Compare you final answers with values from a textbook.

How can you check that a practical result is reproducible?

 A clear set of instructions that will allow valid data to be collected.

A description of how the control variables will be controlled.

A suitable range for the independent variable.

Which of these should be included in a good written method?

The line of best fit passes through the origin (0,0).

The line of best fit is vertical (goes straight up).

A pupil produces a graph to see if there is a relationship between two variables.
What features would the graph have if the variables are directly proportional to each other?

Repeat the experiment until they get results that will give a straight line.

Join the points with a series of straight lines, like a dot-to-dot.

Draw a single straight line from the origin to the last point plotted.

Draw a single curved line that passes through, or close to, the points.

Draw a series of curves through the points.

A pupil produces a graph to see if there is a relationship between two variables. The points do not seem to follow a straight line.
How should they draw a line of best fit?

The time is very short so would produce a very small error in the speed.

The time is very short so would produce a very large error in the speed.

It will not be possible to start and stop the watch accurately.

The distance is too large to estimate instantaneous speed over.

A pupil suggests measuring the time it takes a trolley to roll 5 cm down a ramp using a stopwatch to get an accurate value of instantaneous speed. 
Why is this unlikely to produce an accurate result?

Match the units to the quantity they measure.

$$\text{average speed} = \text{distance} \times \text{time}$$

$$\text{average speed} = \text{distance} + \text{time}$$

$$\text {average speed} = {\text{distance} \over \text{time}}$$

$$\text{average speed} = \text{distance} – \text{time}$$

$$\text{average speed} = \text{distance} \times \text{time}^2$$

A resultant force is acting on the trolley, causing it to speed up. 

Frictional forces are increasing the speed of the trolley.

The trolley is producing more energy as it moves faster.

The mass of the trolley is decreasing as it travels.

Why is the instantaneous speed of a trolley greater at the bottom of the ramp than near the top?

The instantaneous speed is greatest at the bottom of the ramp.

The instantaneous speed is greatest at the top of the ramp.

The greatest instantaneous speed is higher than the average speed.

The greatest instantaneous speed is lower than the average speed.

During an experiment, a trolley rolls down a ramp, getting faster as it moves. 
Which two statements are correct?

Calculate the speed of a trolley if it travels a distance of 10 cm in 0.2 s. 
Give your answer in m/s.

Content guidance

Risk assessment required - equipment

Adult supervision required

This lesson will soon be taken down.

Measuring instantaneous speed analysis (v=s/t)

Lesson outcome

Content guidance