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.
Answer:
is a reflection.
The image is real light rays actually focus at the image location). As the object moves towards the mirror the image location moves further away from the mirror and the image size grows (but the image is still inverted). When the object is that the focal point, the image is at infinity.
Explanation:
Answer is A) Fulcrum
The fixed point that a lever rotates around is called the fulcrum.
To find out scientific notation, you want to make sure that number is less than 10. So do 5.000000, you don't rally need the zeros but I just want to make my point. So use 10^x meaning ten the whatever power adds zeros like 5.000000x10^6 meaning it is increasing it by six zeros moving it out of the decimals and letting become 5,000,000.
<h3>Hello There!!</h3>
<h3><u>Given</u>,</h3>
Force(F) = 150N
Mass(m) = 90kg
<h3><u>To </u><u>Find,</u></h3>
Acceleration(a) = ?
<h3><u>We know,</u></h3>
F= m×a


<h3>Hope this helps</h3>