Answer
a. These are objects in motion that have kinetic energy.
Explanation:
Answer:
The angle is 
Explanation:
From the question we are told that
The length of the wire is 
The current is 
The magnetic field strength is 
The magnitude of the magnetic force is 
Generally the magnetic force exerted on the wire is mathematically represented as

Making
the subject
![\theta =sin^{-1} [ \frac{ F_b }{I * l * B } ]](https://tex.z-dn.net/?f=%5Ctheta%20%3Dsin%5E%7B-1%7D%20%5B%20%5Cfrac%7B%20F_b%20%7D%7BI%20%20%2A%20%20l%20%20%2A%20%20B%20%7D%20%5D)
substituting values
![\theta =sin^{-1} [ \frac{ 0.18 }{ 2.0 * 0.6 * 0.3 } ]](https://tex.z-dn.net/?f=%5Ctheta%20%3Dsin%5E%7B-1%7D%20%5B%20%5Cfrac%7B%200.18%20%7D%7B%202.0%20%20%20%2A%20%20%200.6%20%20%2A%20%20%200.3%20%7D%20%5D)

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.
Much of the precipitation in large bodies of water occurs at the surface. The ocean loses about 37000 km cubed considering evaporation and precipitation.
I believe it is true . Somebody correct me if I’m wrong!