Answer:
It's A
Explanation:
As the waves progress through the medium, the particles they are made of move perpendicular to the direction in which the waves move. The particles do not move with the wave. So waves transmit energy but not matter as they progress through a medium.
The answer is C) A girl hangs by both hands, motionless, from a trapeze.
You need to use Planck's law:
E = h·υ = (h·c)/λ
Without making all the calculations, a fraction is bigger than another when the denominator is smaller. Therefore you need to find the smallest wavelength (λ) which is 450nm.
You could also be helped by colors: in order of decreasing energy, you have blue - green - yellow - red.
In any case, the correct answer is a).
Answer:

Explanation:
We can solve this problem by using Newton's second law of motion, which states that the net force acting on an object is equal to the product between its mass and its acceleration:

where
F is the net force on the object
m is its mass
a is its acceleration
In this problem:
F = 40 N is the force on the object
m = 2 kg is its mass
Therefore, the acceleration of the object is

a whip used as an instrument of punishment
a person or thing that causes great trouble or suffering.