Answer:
By examining its external shape, color, hardness, etc.
Explanation:
Here, we are given with:

(a) So now, we can thus obtain



Now, finding 


Now, finding k


Thus, expression for the electric field is:

(b) Now, here


Thus, expression for the magnetic field:

(c) The electromagnetic wave propagates along Z-axis
You need to observe the car at two different times.
-- The first time:
You write down the car's speed, and the direction it's pointing.
-- The second time:
You write down the car's speed and the direction it's pointing, again.
You take the data back to your lab to analyze it.
-- You compare the first and second speed. If they're different,
then the car had acceleration during the time between the two
observations.
-- You compare the first and second direction. If those are different,
even if the speeds are the same, then the car had acceleration during
the time between the two observations.
(Remember, "acceleration" doesn't mean "speeding up".
It means any change in speed or direction of motion.)
Answer:
B. There are no forces acting on the ball.
Explanation:
There are no forces acting on the ball.
The answer is C. in sort of a way. You can't technically see black matter. However, it is holding the galaxies together.