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How to Calculate Distance Based on Kinetic Energy

Kinetic energy is the product of an object's mass, or weight, and its velocity. If you throw a ping-pong ball across the room, for example, you exert a force on the ping-pong ball that accelerates the ping-pong ball. This force becomes the kinetic energy of the flying ping-pong ball. Physicists write the formula for kinetic energy (KE) as KE = 1/2mv^2, in which m represents mass and v represents velocity. The units used to measure kinetic energy are Joules.

Things You'll Need

Pencil
Paper
Calculator

Instructions

- 1
  Write the velocity of a car in meters per second to determine the car's stopping distance based on its kinetic energy. Stopping distance is a useful measurement because it includes friction. Without friction, according to Newton's First Law, a moving object will never stop moving; it will travel an infinite distance. For example, write "17 meters per second (55.77 feet per second)."
- 2
  Square the velocity you have written using a calculator. For example, 17 x 17 = 289.
- 3
  Write the coefficient of static friction. This number represents the amount of friction between two objects, such as the tires of a car and the road. According to C. R. Nave, 0.8 is an appropriate value for the coefficient of static friction between "good" tires and a "good" surface. For example, write "0.8."
- 4
  Multiply the coefficient of friction you have written by 2. For example, 0.8 x 2 = 1.6.
- 5
  Multiply your answer by the acceleration of gravity in meters per second squared (m/s^2) using a calculator. The acceleration of gravity in meters per second squared is approximately 9.8 m/s^2 (32 feet per second squared). For example, 1.6 x 9.8 = 15.68.
- 6
  Find the quotient of your answer and the square of the car's velocity you calculated. For example, 289/15.68 = 18.43112245. The stopping distance of the car will be approximately 18.4 meters (60.4 feet).

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