How to Calculate Terminal Velocity in a Fall
- 1). Multiply the object's mass by the acceleration due to gravity. The gravitational constant varies according to the object's location on the earth, but an average value you can use is 9.80665 meters per second squared.
- 2). Double the product in Step 1 to find the value of 2 mg or (2 * mass * the gravitational constant).
- 3). Find the drag coefficient of the object. The amount of drag or air resistance on an object depends on the object's shape. The procedure for calculating drag coefficient is in itself a complex equation, but the drag coefficient equation and estimates for various objects can be found in the Resources section.
- 4). Find the frontal area of the object. This term can be thought of as the surface area of the object that will be exposed to airflow as it falls, or as the cross-sectional area of the front of the object.
- 5). Multiply the drag coefficient (Step 3) by the frontal area of the object (Step 4) to find the value of Cd * Af.
- 6). Find the density of the medium through which the object is falling. Air density varies with changes in temperature and humidity, but its approximate density at 15 degrees Celsius from sea level is 1.22521 kg/m.
- 7). Multiply the values of Steps 5 and 6.
- 8). Divide the value in Step 2 by the value in Step 7.
- 9). The terminal velocity is the square root of the value in Step 8.
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