Applying enough force to an object to cause it to move gives kinetic energy to that object. For example, when you throw a ball it moves because your throwing motion transfers energy to the ball. The speed of the ball also depends on its mass --- you can throw a baseball faster than a basketball because it weighs less, and thus requires less kinetic energy to reach the same speed. The only variables in the physics equation for kinetic energy are kinetic energy, mass and velocity, so you can calculate velocity using this equation when you know the other two variables.
Instructions
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1
Multiply the kinetic energy by 2. If the object has a kinetic energy of 10 Joules, for example, 2 * 10 J = 20 J.
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2
Divide the result by the mass of the object. If the object has a mass of 5 kg, 20 J/5 kg = 4 m^2/s^2. A Joule is equivalent to one (kg*m^2)/s^2, so when you divide it by kg, you get units of m^2/s^2.
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3
Take the square root of the result to find the speed of the object. For example, sqrt(4 m^2/s^2) = 2 m/s.