# 3Move-3

## Outcomes

• Pupils can confidently rearrange the speed equation
• Pupils can apply the speed equation to various situations
• Pupils can convert between different units for speed

## Specification References

1.3 recall and use the relationship between average speed, distance moved and time: average speed = distance moved / time taken

## Starter

• Put a couple of speed conundrums on the board (when do two trains/cars pass)

e.g. Boston and New York are approximately 280 miles apart. One Train leaves Boston traveling towards New York at an average speed of 80mph. Another train leaves New York at the same time traveling toward Boston at an average speed of 60 mph. (a) How long will it take them to meet? (b) How far has the Boston train traveled when they meet? (2h and 160 miles).

or

A person rides from London to Brighton (approximately 50 miles) at an average speed of 20 mph and then drives his car home at an average speed of 60 mph. What is his average speed [p.s. it's not 40 mph] - (30 mph)

## Main Body of Lesson

• Rearrange the speed equation without going through the equation specifically, i.e. try to do it through words and the meaning of the quantities e.g. if I'm covering 5 m per/every second how far will I go in 10 seconds. Lead this into forming the equation. The final version (t = d/s) is trickier to visualise, try it with some simple numbers (e.g. moving at 20m/s over a course of 100m, how long will it take)
• Rearranging equations – go through a method for rearranging equations (such as diagonal movement for simple equations or standard maths cancellation)
• I have a worksheet somewhere for practicisicisng this. (AGR)
• In addition it could be a good time to get them to convert from mph to km/h or m/s to km/h. There is a ppt called "speed conversions" if you like

## Plenary

• Practice questions on rearranging (add some tricky ones at the end e.g. KE or T pendulum for extension). Sheet in shared folder.

## Homework

speed questions with some miles and kilometers in and rearrangements needed