Measuring Speed

• • Speed is the distance travelled by an object every second.
• • The simplest way to measure the speed of an object, is to time how long it takes to travel a known distance and use the equation:

  
• Choosing Equipment:

  • To ensure a result for speed is as accurate as possible, choose the appropriate equipment to measure the distance and time.

  
• It would not be practical to use a metre rule to measure the length of an athletics track though.

  • In this instance, a more appropriate piece of equipment would be a (long!) tape measure, or even better, a trundle wheel
• A light gate can be used to start a timer when an object passes through it.

  • A flag on top of the moving object blocks a beam of light as it passes through the light gate, triggering the timer to start
  • A second light gate (at some fixed distance away) can be used to stop the timer as the object passes through it
• Single Light Gates to Measure Speed:

  • A single light gate can also be used to measure the speed of an object as it passes through.

  
• Example of using a single light gate to measure speed:

  • The timer measures how long the light gate is blocked for
  • The distance travelled is given by the length of the flag passing through the light gate
  • The two measurements for distance travelled and time taken can then be used in the equation for speed
• Using Lights Gates to Measure Time:

  • Light gates are pieces of digital equipment that allow times to be measured more accurately.