Answer:
180 W
Explanation:
The work done by the man against gravity is equal to its gain in gravitational potential energy:

where
(mg) = 720 N is the weight of the man
is the change in height
Substituting,

The power he must deliver is given by

where
W = 3600 J
t = 20 s is the time taken
Substituting,

The correct answer is C. Taiga hope it helps ( :
The ball is travelling faster when the two objects hits the level ground below.
<h3>Time of motion of the objects</h3>
The time of motion of the objects depends on height and initial velocity of projection of the objects.
The stone has no initial vertical velocity while the ball has initial vertical velocity.
Thus, the ball is travelling faster when the two objects hits the level ground below.
Learn more about time of motion here: brainly.com/question/2364404
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However instead of crests and troughs, longitudinal waves have compressions and rarefactions. Compression. A compression is a region in a longitudinal wave where the particles are closest together. Rarefaction. A rarefaction is a region in a longitudinal wave where the particles are furthest apart.