Answer:
56 N
Explanation:
There are only two forces acting on the package:
- The force of gravity, directed downward, equal to
[tex]mg[/tex]
where m is the mass of the package and g is the acceleration due to gravity
- The air resistance, acting upward, let's label it with [tex]R[/tex]
According to Newton's second law, the resultant of the two forces must be equal to the product between the mass, m, and the acceleration, a:
[tex]mg-R=ma[/tex]
where we have:
m = 20.0 kg
g = 9.8 m/s^2
a = 7.0 m/s^2 is the acceleration when the package is at 25 m above the ground.
Substituting into the equation, we can find the magnitude of the air resistance at that altitude:
[tex]R=mg-ma=m(g-a)=(20.0 kg)(9.8 m/s^2-7.0 m/s^2)=56 N[/tex]
