A 7.0kg skydiver is descending with a constant velocity

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Physics Kim Chi 3 years 2021-09-03T03:07:09+00:00 2021-09-03T03:07:09+00:00 1 Answers 13 views 0

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thuthao · Answer 1 · 2021-09-03T03:08:32+00:00

Answer:

Air resistance: 68.6 N

Explanation:

For the skydiver falling down, there are two forces acting on him:

– The force of gravity, of magnitude

$W=mg$

where

m = 7.0 kg is the mass of the skydiver

$g=9.8 m/s^2$ is the acceleration of gravity

This force acts in the downward direction

– The air resistance, R, in the upward direction

So the net force on the skydiver is:

$\sum F=mg-R$

According to Newton’s second law of motion, the net force is also equal to mass times acceleration:

$\sum F=ma$

However, in this problem the skydiver is falling at constant velocity, so his acceleration is zero:

$a=0$

Therefore, the net force is zero:

$\sum F=0$

And so we can find the magnitude of the air resistance, which is equal to the weigth of the skydiver:

$mg-R=0\\R=mg=(7.0)(9.8)=68.6 N$