How to Find Speed From Distance & Mass

Mathematics instructs us that speed = distance/time. It is possible, however, to calculate speed from a different approach, using distance and acceleration variables, if distance and time are not both available. Speed, or velocity, is determined by: Final velocity squared -- initial velocity squared = 2(acceleration*displacement). Follow the steps and you can determine the speed for your mathematical problem.

• 1

  Determine the time, or initial velocity. If that is not available, then the calculation can only be made assuming that it started from rest.

• 2

  Use the equation, vf^2 -- vi^2 = 2ad, where "vf" represents the final velocity, "vi" is the initial velocity, "a" is acceleration and "d" equals the displacement.

• 3

  Note that acceleration equals -9.8 meters per second since it is a free fall. The mass amount does not change the formula because all objects accelerate at the same rate when falling downward.

• 4

  Use the formula, velocity = mass x acceleration, and calculate the final velocity by following these steps:

  vf^2 - 0 = 2(-9.8)(-0.05)

  vf = root(0.98)

  vf = 0.99 m/s

• 5

  Take the final velocity/speed amount, or 0.99 meters per second, and plug it into the basic formula for speed:

  speed = distance/time.