<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.
The angular speed is defined as:
<h2> ω=

</h2>
where



Answer:
The 10X objective is use for the identification of actual size of histology tissues and 4X magnification is best for observation of most tissues slides
Explanation:
4X magnification is best for observation of most tissues slides because it has an objective lens that have lower power and have great high field overview which make it very easier to locate specimens on the slide. It is use to get the overview of histology slides. It is use to showcase more detailed observations about histology.
The 40X objective is use majorly to identify tissue , to observe the finer details and study tissue organization on the histology slide.
To solve this problem it is necessary to apply the concepts related to the Centrifugal Force and the Gravitational Force. Since there is balance on the body these two Forces will be equal, mathematically they can be expressed as


Where,
m = Mass
G =Gravitational Universal Constant
M = Mass of the Planet
r = Distance/Radius
Re-arrange to find the velocity we have,

At the same time we know that the period is equivalent in terms of the linear velocity to,


If our values are that the radius of mars is 3400 km and the distance above the planet is 100km more, i.e, 3500km we have,



Replacing we have,



Therefore the correct answer is C.