Correct Answer to Question 11

At first the sky diver has an acceleration g due to the earth's gravitational pull. But as the sky diver's velocity increases, the effects air resistance also increase because the force of air resistance is proportional to the velocity of the falling object. Thus, as the velocity of the object increases, the force opposing the motion of the object increases.

Let W equal the weight of the sky diver and R equal the air resistance force. At first R has a small value because the downward velocity is small.

As time goes on and the sky diver's velocity continues to increase due to gravitational acceleration, the value of R increases. Gradually the net downward force Fd gets smaller and smaller.

Fd = W - R

Whenfinally the air resistance force R is equal to the earth's gravitational force W, the net downward force is zero. The sky diver continues to fall toward the earth, but at a constant velocity. This velocity is called "terminal velocity".

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