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22. mainidea the skydiver shown in figure 13 falls at a constant speed in the spread-
eagle position. immediately after opening the parachute, is the skydiver accelerating? if
so, in which direction? explain your answer using newton's laws.

Yes, upward

Explanation:

We can solve the problem by using Newton's second law, which can be written as

where is the net force, m is the mass, a is the acceleration.

At the beginning, the skydiver is falling at constant speed (called terminal velocity): this means that the two forces acting on him/her, the weight W (downward) and the air resistance R (upward) are equal in magnitude, and so the net force (and the net acceleration) is zero:

When the parachute is opened, the resistance  force suddenly increased (because the surface area of the body increases), so Newton's second law becomes:

this time, , therefore , which means that the acceleration has the same direction as the air resistance (upward). As a result, the skydiver will accelerated upward, which means that its vertical velocity will decrease in magnitude (because he/she was travelling downward, so the acceleration is in the opposite direction).

be subject to a force andchange its motion