The correct choice is
D. 22 Hz and 42 Hz.
In fact, the beat frequency is given by the difference between the frequencies of the two waves:
In this problem, the beat frequency is 
, therefore the only pair of frequencies that gives a difference equal to 20 Hz is
D. 22 Hz and 42 Hz.
Answer:
To calculate displacement, simply draw a vector from your starting point to your final position and solve for the length of this line. If your starting and ending position are the same, like your circular 5K route, then your displacement is 0. In physics, displacement is represented by Δs.
Explanation:
hope helps
"<span>An atom is the smallest unit of matter and an element is a pure substance that is made of identical atoms" is correct. Although atoms can be broken down further now, it still take a whole atom to make an element. </span>
The acceleration due to gravity on Earth is 9.8 m/s per second.
