1. MEASURING SPEED

2. Measuring speed is very hi-tech nowadays but before this technology was developed the police relied on the same method of measuring speed that you are going to use today. This manual method relied on the use of a stopwatch to measure the time it took for a vehicle to pass between two fixed positions. Police set a ‘speed trap’ by carefully measuring a section of road. One officer was stationed (often hidden) at either end of the section. When a car passed the first officer he raised his hand and the second officer started his stopwatch – stopping it when the car passed him.

3. The speed could then be calculated – the police officers generally used tables with these calculations already done for them but you are going to calculate them using the formula Speed = Distance Time The units that are used to measure the distance and the time will determine what units the speed will be given in.

4. The experiment You are going to use this method to measure peoples’ speed for walking and running. You will need to carefully measure the distance between which the person’s speed will be measured. How long do you think it should be ? This distance should be marked at either end. In groups of three one person must stand at either end of the distance. The person whose speed is being measured can take a walk/run up but when they pass the first marker the first measurer must shout start and the person at the second marker will start the stopwatch. The stopwatch is pressed again when the runner passes the second marker. The time and distance are then recorded.

5. The speed is then calculated. For example if someone had run 30 metres in 15 seconds then the calculation would be Average speed = 30/15 = 2 metres per second Can you convert this into km per hour ?