The speed of the ball is B. 5 meters per second
Explanation:
For an object in uniform motion (= at constant velocity), the speed can be calculated using the equation

where
v is the speed
d is the distance covered
t is the time taken
For the ball in this problem:
d = 50 m is the distance covered
t = 10 s is the time taken
Substituting, we find the speed:

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Answer:

Explanation:
The energy lost due to air friction is equal to the mechanical energy lost by the parachutist during the fall.
The initial mechanical energy of the parachutist (at the top) is equal to his gravitational potential energy:

where
m = 20.1 kg is his mass
is the acceleration due to gravity
h = 662 m is the initial heigth
The final mechanical energy (at the bottom) is equal to his kinetic energy:

where
v = 7.12 m/s is the final speed of the parachutist
Therefore, the energy lost due to air friction is:

Answer:
The magnetic stripes might reverse direction. The deep-ocean trench might become deeper.
Explanation:
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