D. <span>Johannes Kepler argued that Earth was the center of the universe.
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Answer:
4515.49484 N
4329.10484 N
Explanation:
r = Radius of balloon = 4.4 m
m = Mass of balloon with instruments = 19 kg
g = Acceleration due to gravity = 9.81 m/s²
Volume of balloon

The Buoyant force = Weight of the air displaced

The buoyant force acting on the balloon is 4515.49484 N
Net force on the balloon

The net force on the balloon is given by 4329.10484 N
As the balloon goes up the pressure outside reduces as the density of air decreases while the air pressure inside the balloon is high hence, the radius of the balloon tend to increase as it rises to higher altitude.
The answer to this question is true I believe
Answer:
176.4 m
Explanation:
U = 0, t = 6s, g = 9.8 m/s^2
Use second equation of motion
H = ut + 1/2 gt^2
H = 0 + 0.5 × 9.8 × 6 × 6
H = 176.4 m
It is the displacement from the point of dropping of object.