348.34 m/s. When Superman reaches the train, his final velocity will be 348.34 m/s.
To solve this problem, we are going to use the kinematics equations for constant aceleration. The key for this problem are the equations
and
where
is distance,
is the initial velocity,
is the final velocity,
is time, and
is aceleration.
Superman's initial velocity is
, and he will have to cover a distance d = 850m in a time t = 4.22s. Since we know
,
and
, we have to find the aceleration
in order to find
.
From the equation
we have to clear
, getting the equation as follows:
.
Substituting the values:

To find
we use the equation
.
Substituting the values:

Answer: The skier has potential and kinetic energy.
Explanation: This is what I found from a different user on this website
Answer:

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Explanation:
From the exercise we know two information. The real speed and the experimental measured by the speedometer

Since the speedometer is only accurate to within 0.1km/h the experimental speed is

Knowing that we can calculate Kinetic energy for the real and experimental speed


Now, the potential error in her calculated kinetic energy is:

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