What must happen to the electric current in power lines before it can safely enter your home?
2 answers:
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Answer:
The distance between the two objects must be squared.
Explanation:
Gravitational force always act between two objects that have mass. The gravitational force is a weak force and attractive in nature.
The force of pull depends on the masses of the two objects and the distance between them.
The formula to calculate gravitational force between two objects having masses 'm' and 'M' and separated by a distance 'd' is given as:
Where, 'G' is called the universal gravitational constant and its value is equal to .
Now, from the above formula, it is clear that, the force of gravitation is inversely proportional to the square of the distance between the two objects.
Thus, the quantity that must be squared in the equation of gravitational force between two objects is the distance 'd'.
Answer:
The rotational kinetic energy takes 0.430 seconds to become half its initial value.
Explanation:
By the Principle of Energy Conservation and the Work-Energy Theorem we know that flywheel slow down due to the action of non-conservative forces (i.e. friction), the energy losses are equal to the change in the rotational kinetic energy. That is:
(1)
Where:
- Energy losses, measured in joules.
,
- Initial and final rotational kinetic energies, measured in joules.
By definition of rotational kinetic energy, we expand the equation above:
(2)
Where:
- Moment of inertia of the flywheel, measured in kilograms per square meter.
,
- Initial and final angular speed, measured in radians per second.
If we know that ,
and
, then the initial angular speed is:
(3)
(4)
Under the assumption that flywheel is decelerating uniformly, we get that the time taken for the flywheel to slowdown is:
(5)
If we know that ,
and
, then the time needed is:
The rotational kinetic energy takes 0.430 seconds to become half its initial value.