Motion with Constant Acceleration (Freefall)

Freefall    

The importance of the One-Dimensional Motion with Constant Acceleration model in the mechanics curriculum owes much to the fact that one of the most prevalent interactions in our environment, gravity gives rise to a constant force on every object near the earth's surface. Thus, any object moving purely under the influence of gravity near the earth's surface will experience a constant acceleration. This type of motion is common enough in everyday experience that it receives the special name freefall.

Freefall: An object that is subject only to the force of gravity is in freefall.

More surprisingly, the acceleration is also almost exactly the same on every object in freefall near the earth! The acceleration of gravity on any object in freefall near the earth's surface is well approximated by the value of 9.8 m/s² directed toward the ground. The magnitude of the gravitational acceleration is so widely used in mechanics that we assign it a special constant, g.