Notice that a ball dropped from rest eventually reaches a constant speed called the terminal speed. This is equal to g/k where g is the acceleration due to gravity and k is a constant that is proportional to the force of air resistance at a certain speed. You can set a value of k before clicking on a link in order to observe its effect on the motion of the projectile.
Answer the following questions:
1. Suppose a skydiver is falling at her terminal speed when she pulls her 'chute. During the time interval that the chute opens, what direction is her acceleration?
2. If a projectile is projected downward with an initial speed greater than g/k, the object's terminal speed, is its instantaneous acceleration, at any instant before it reaches terminal speed, positive or negative?
|Position vs. Time
Velocity vs. Time
Acceleration vs. Time
|Ball dropped from rest||Ball projected downward with initial speed greater than the terminal speed (vterm=g/k)||