A 900-kg car cruising at a constant speed of 60 km/h is to accelerate to 100 km/h in 4 s. The additional power needed to achieve
1 answer:
To solve this problem we will apply the concepts related to power as a function of the change of energy with respect to time. But we will consider the energy in the body equivalent to kinetic energy. The change in said energy will be the difference between the two velocity data given by half of the mass. We will first convert the given units into an international system like this
Initial Velocity,
Final Velocity,
Now Power is defined as the change of Energy over the time,
But Energy is equal to Kinetic Energy,
Replacing,
Therefore the correct answer is A.
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Answer:
d) 0 V
Explanation:
It can be showed that the potential due to a point charge q, to a distance d from the charge, can be expressed as follows:
where k =
As the potential is an scalar, and is linear with the charge, we can apply the superposition principle, which means that we can find the potential due to one of the charges, as if the other were not present.
By symmetry, all four charges are at the same distance from the center, so we can write the total potential, as follows:
where d, is the semi-diagonal of the square, that we can find applying Pythagorean theorem, as follows:
Replacing by the values in (1) we have:
which is equal to the option d).