A dynamics trolley is a wheeled object used in experiments. It moves very smoothly over flat surfaces.

The average speed is the total distance travelled divided by the total time for a journey.

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

An anomalous reading is a result which is significantly outside the pattern in a set of results.

Measuring instantaneous speed practical (v=x/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

the total distance travelled divided by the time taken

the speed of an object at a particular moment

a wheeled object used in motion experiments

a result which does not fit the pattern of a set of results

Match the key words or phrases to their definitions.

The instantaneous speed of an object is always less than the average speed.

The instantaneous speed of an object is always greater than the average speed. 

The instantaneous speed of an object is always the same as the average speed.

The instantaneous speed of an object can change during a journey.

The instantaneous speed of an object is constant during any journey.

Which of these statements about instantaneous and average speed is correct?

the speed of the trolley at the end of the ramp

A student investigates the relationship between the steepness of a ramp and the instantaneous speed of a trolley at the end of the ramp. Which of these are control variables for the investigation?

A trolley rolls down a ramp and passes between two markers that are 20 cm apart in a time of 0.25 s. 
Calculate the speed of the trolley in m/s.

mean time = (0.25 + 0.23 + 0.35 + 0.22 + 0.21) ÷ 5

mean time = (0.25 + 0.23 + 0.22 + 0.21) ÷ 5

mean time = (0.25 + 0.23 + 0.35 + 0.22 + 0.21) ÷ 4

mean time = (0.25 + 0.23 + 0.35 + 0.22) ÷ 4

mean time = (0.25 + 0.23 + 0.22 + 0.21) ÷ 4

A pupil collects the following set of timing data for a moving object: 0.25 s, 0.23 s, 0.35 s, 0.22 s, 0.21 s.
Which calculation should the pupil use to find the mean time?

A trolley rolls down a ramp passing between two markers, 0.20 m apart. The following results are collected: 0.17 s, 0.18 s, 0.17 s, and 0.20 s.
Calculate the mean instantaneous speed for the trolley.

Izzy rode her bike for 3 hours and travelled 45 kilometres. 
What was her average speed?

Lucas rides his bike for 4 hours with an average speed of 15 km/h. He travelled at a speed of 10 km/h for the first two hours.
What speed must he have been travelling at for the last two hours?

Which of the graphs shows an object moving with increasing speed (accelerating)?

Andeep ran 20 metres in 5 seconds then slowed down and walked 5 metres in the next 5 seconds. 
What was his average speed for the first 5 seconds?

Andeep ran 20 metres in 5 seconds then slowed down and walked 5 metres in the next 5 seconds. 
What was his average speed for the whole 10 seconds?

Aisha cycles to school three days in a row. Her speeds are shown on the bar chart. 
What is her average speed for the journey to school?

This lesson will soon be taken down.

Measuring instantaneous speed practical (v=x/t)

Lesson outcome