Velocity and Speed

Motion
What happens when you move? Velocity is a measure of how fast and in what direction an object is going. Speed is a measure of the rate at which the objects moves over a distance
 * You change your location
 * You may change your direction
 * You change your position as time goes on

Speed = Distance/Time (The unit is either km/h or m/s)

Velocity = Displacement/Time

Velocity is a measure of the rate of change in position over time and hence the direction must be stated.

VELOCITY has a DIRECTION as well as a MAGNITUDE.

Distance indicates length in metres (m) and displacement indicates distance with its direction of movement

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Measuring Speed
Physics lab measures and analyses speed by using a ticker timer.

Speed is usually measured by using a stop watch in many events.

The police use three different methods to measure the speed of vehicles on the road. They include:
 * Radar guns and mobile radar units, based on change in radio frequency of the waves of a moving car (Instantaneous speed).
 * Laser guns, based on reflected light pulses at target moving vehicle (instantaneous speed).
 * Digitectors (amphometers), based on sound of a vehicle recorded by two parallel cables (average speed).

Ticker Timer
A small electric hammer strikes a piece of carbon paper at 50 times a second. So the distance between two dots is produced every 0.02 seconds.