<h2>Answer: electrostatic and gravitational force
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Mechanical energy remains constant (conserved) if only <u>conservative forces</u> act on the particles.
In this sense, the following forces are conservative:
-Gravitational
-Elastic
-Electrostatics
While the Friction Force and the Magnetic Force are not conservative.
According to this, mechanical energy is conserved in the presence of electrostatic and gravitational forces.
Answer:

Explanation:
Torque is defined as the cross product between the position vector ( the lever arm vector connecting the origin to the point of force application) and the force vector.

Due to the definition of cross product, the magnitude of the torque is given by:

Where
is the angle between the force and lever arm vectors. So, the length of the lever arm (r) is minimun when
is equal to one, solving for r:

True, for electricity fossil fuels are burned to turn a steam turbine to generate electricity and natural gas is exactly what it says gas formed from the decay of plant and animal life long ago
The vessel must also have red and green side lights.
The red light is placed on the port (left) side of the boat while the green light is placed on the starboard (right) side of the vehicle. The white lights are on both the masthead (front) and stern (rear) of the boat, unless the vessel is less than 39.4 feet, in which case the front and rear white light may be combined as only one white light.