The speed of the rock at 20 m is 34.3 m/s
Explanation:
We can solve this problem by using the law of conservation of energy: the mechanical energy of the rock, sum of its potential energy + its kinetic energy) must be conserved in absence of air resistance. So we can write:
where
:
is the initial potential energy
is the initial kinetic energy
is the final potential energy
is the final kinetic energy
The equation can also be rewritten as follows:
where:
m = 100 kg is the mass of the rock
is the acceleration of gravity
is the initial height
u = 0 is the initial speed (the rock starts at rest)
is the final height of the rock
v is the final speed when h = 20 m
And solving for v, we find:

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1. B. Hemo is on a machine, peritoneal is in the abdomen
2. B. Nothing is as good as having your own kidney, and not everyone is a good candidate for all types of dialysis.
3. Also B. Peritoneal dialysis is done over a longer period of time, up to 24 hours. Hemodialysis is done in a few hours. Your kidney works 24/7.
The kinetic energy and gravitational potential energy changes during its movement from ground to the top height.
<h3>What happens to kinetic and potential energy while motion?</h3>
When the ball moves upward, its gravitational potential energy is increases and kinetic energy begins to decrease but when the ball falls towards the earth, its gravitational potential energy is transformed into kinetic energy. When the ball collides with the ground, the kinetic energy is transformed into other forms of energy.
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10.92N
Explanation:
Given parameters:
Mass of truck = 2.964kg
Velocity of truck = 7m/s
Time taken = 1.9s
Unknown:
Average force on the car = ?
Solution:
According to newton's third law of motion "action and reaction are equal and opposite".
The force with which the truck struck the fence is the same as the force the fence acted on the truck with but in another direction.
From newton's second law:
Force = mass x acceleration
We know that acceleration is the change in velocity with time;
acceleration =
Force = mass x
Force =
= 10.92N
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