The answer is the option c. generator. Generator is a machine that
converts mechanical energy into electricity. The way it is made is
because the mechanical movement may be transformed in rotation of
magnets placed inside a coiled wire, and this induces the movement of
electrons through the coiled wire. As you know electricity is the flow
of electrons.
Good morning.
We have:

Where
j is the unitary vector in the direction of the
y-axis.
We have that

We add the vector
-a to both sides:

Therefore, the magnitude of
b is
47 units.
First, you find what 20% of 10 gallons of gas would be. This will show how many gallons the car actually uses.
10 gallons x 20% =
10 x 0.20 =
2 gallons used
Then you subtract that number from the total 10 gallons to get how many gallons of gas would be wasted.
10 gallons - 2 gallons =
8 gallons of gas wasted
Question 18: a
question 19: b
question 20: c