The correct answer is:
<span>B.) At terminal velocity there is no net force
In fact, when the parachutist reaches the terminal velocity, his velocity does not change any more. It means that the acceleration acting on the parachutist is zero, and for Newton's second law, this means the net force acting on him is zero:
</span>

<span>because the acceleration is zero: a=0.
This also means that the two relevant forces acting on the parachutist (gravity, downward, and air resistance, upward) are balanced to produce a net force equal to zero.</span>
Force = mass x acceleration
Force = 4kg x 10m/s^2
Force = 40N
Explanation:
d= 80km = 8000m
t = 45 min = 45/60 h
= 0.75 h
V= ?
we know that,
V = d /t
or,V= 80 km / 0.75 h
- or, V= 106.67 km/hr
or,V= 106.67×1000m / 3600 s
2. or, V= 29.63 m/s
Answer:
44.7 N
Explanation:
The gravitational force between the objects is given by:

where
G is the gravitational constant
m and M are the masses of the two objects
r is the distance between the centres of the two objects
In this problem, we have:
is the mass of the sphere
is the Earth's mass
is the Earth's radius, while h=310 km is the altitude of the sphere, so the distance of the sphere from Earth's centre is

Substituting into the equation, we find
