What Happens When an Object is in Free Fall?
An object in free fall is under the influence of gravity. The acceleration due to gravity of planet Earth is -9.8 m/s^2 or -32.2 ft/s^2. Therefore, an object in free fall will experience an a downward acceleration of -9.8 m/s^2 in the absence of air resistance. The vertical velocity of the object will decrease by 9.8 m/s every second. In two seconds, the vertical velocity will decrease (or become more negative) by 19.6 m/s.
An Important Concept to Understand:
Even though the vertical velocity is decreasing by 9.8 m/s every second, the speed is increasing by 9.8 m/s every second. Speed is always positive, but velocity can be positive or negative depending on the direction of the object. As the vertical velocity of the free-falling object decreases from 0 to -9.8 m/s to -19.6 m/s to -29.4 m/s per second, the speed of the object is increasing form 0 to +9.8 m/s to +19.6 m/s to +29.4 m/s per second.
The Meaning of the Variables In The Free Fall Equations:
Vf represents the final velocity and Vo represents the initial velocity. g is the acceleration due to gravity which is -9.8 m/s^2. t is the time which is usually in seconds.
Introduction to Acceleration and Velocity:
Kinematics In One Dimension:
Motion Time Graphs - Velocity Time Graphs: