Answer:

Explanation:
Since work done is in the form of potential energy, we will use the formula of potential energy here.
We know that,
<h3>P.E. = mgh </h3>
Where,
m = mass = 20 kg
g = acceleration due to gravity = 10 m/s²
h = vertical height = 20 m
So,
<h3>Work done = mgh</h3>
Work done = (20)(10)(20)
Work done = 4000 joules
Work done = 4 kJ
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Answer:
a. It is constant the whole time the ball is in free-fall
Explanation:
If we divide the movement on its vertical and horizontal components, and we concentrate on the vertical component, let's call x-component, and analyze Newton's second's law:

with
,
the acceleration on horizontal direction and m the mass of the ball, because the only force acting on the object is gravity that is always vertical, there're not forces on the horizontal direction that means
and by (1) that implies
=0 there's not acceleration on horizontal direction.
Because acceleration is the rate at what velocity changes and there's no acceleration, there's no change in velocity, in other words velocity is constant on horizontal direction.
Answer:
Frequency, f = 7.57 Hz
Explanation:
It is given that,
Capacitance, 
Capacitive reactance, 
We need to find the frequency. The capacitive reactance of the capacitor is given by :

f is the frequency


f = 7.57 Hz
Hence, this is the required solution.
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