Speed and velocity are terms that are often interchanged. They are not, however, identical. Speed is a scalar entity that describes how fast a body is moving. Velocity is a vector, so it not only includes information about how fast a body is moving, but also about the direction in which the body is moving. Velocity is typically expressed in the SI units of meters per second. Your everyday movements like driving or walking are most often given in miles per hour. Including a direction for your motion and choosing SI speed units will convert your speed to velocity.
Instructions
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1
Multiply the speed in miles per hour by 1,609 to obtain a speed in meters per hour. For example, 10 mph = 10 x 1,609 = 16,090 meters per hour.
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2
Divide the speed in meters per hour by 3,600 to obtain a speed in meters per second. For example, 16,090 meters per hour = 16,090/3,600 = 4.469 meters per second.
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Add a direction for the motion to convert from a speed to a velocity. For example, if you are traveling with a speed of 10 mph in a northerly direction, your velocity would be expressed as velocity = (10 x 1,609)/3,600 = 4.469 m/s N.