Answer:
B) A stack of books is carried at waist level across a room
Explanation:
Work is defined as:

where
F is the force applied
d is the displacement of the object
is the angle between the direction of the force and of the displacement
From the formula, we see that the work done is zero when the force and the displacement are perpendicular to each other. Let's now analyze each situation:
A) A bookcase is slid across carpeting. --> work is done, because the force that pushes the bookcase is in the same direction of the displacement
B) A stack of books is carried at waist level across a room. --> no work is done, because the force to carry the book is vertical, while the displacement of the books is horizontal
C) A chair is lifted vertically with respect to the floor. --> work is done, because the force that lifts the chair is vertical, and the displacement is vertical as well
D) A table is dropped onto the ground. --> work is done, because the force of gravity (that makes the table falling down) is vertical and the displacement of the table is also vertical.
I’m not sure what you are asking
The cornea is responsible of refraction light 1/3 in eye.
<h3>What is the function of the cornea?</h3>
In addition to the protective function, it plays a fundamental role in the formation of vision. Transparent, it works like a lens over the iris, focusing light from the pupil towards the retina.
Normally, the cornea and lens deflect (refract) incoming light rays, focusing them on the retina. The shape of the cornea is fixed, but the lens changes shape to focus on objects at different distances from the eye.
See more about cornea at brainly.com/question/2297282
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Answer:
The height at wich the object floats
Explain
took on edge 2020