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
[tex]W=mg[/tex]
where
m = 7.0 kg is the mass of the skydiver
[tex]g=9.8 m/s^2[/tex] 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:
[tex]\sum F=mg-R[/tex]
According to Newton's second law of motion, the net force is also equal to mass times acceleration:
[tex]\sum F=ma[/tex]
However, in this problem the skydiver is falling at constant velocity, so his acceleration is zero:
[tex]a=0[/tex]
Therefore, the net force is zero:
[tex]\sum F=0[/tex]
And so we can find the magnitude of the air resistance, which is equal to the weigth of the skydiver:
[tex]mg-R=0\\R=mg=(7.0)(9.8)=68.6 N[/tex]
