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.
The step of this scientific method is "draw conclusion".
<h3>What is scientific method?</h3>
The scientific method is the process of objectively establishing facts through testing and experimentation.
The basic scientific process or scientific method involves the following;
- making an observation
- forming a hypothesis
- making a prediction
- conducting an experiment
- analyzing the results and
- drawing conclusion.
Thus, if Kim’s experiment showed that chicken eggshells were stronger when she gave the hen feed, to which extra calcium had been added. The step of this scientific method is "draw conclusion".
Learn more about scientific method here: brainly.com/question/17216882
#SPJ1
They are too small are never in the same place. Electrons are constantly moving in random motion within the electron cloud, making them impossible to follow.
Answer:
Explanation:
7.0 - 4.0 = 3.0 kg water
3.0 kg(2.26 x 10⁶ J/kg = 6.78 x 10⁶ J
220 V(15 A) = 3300 W
1 W = 1 J/s
6.78 x 10⁶ J / 3300 J/s = 2054 s
2054 s / 60 s/min = 34 min
To solve this problem we will apply the work theorem which is expressed as the force applied to displace a body. Considering that body strength is equivalent to weight, we will make the following considerations
Work done to upward the object
Horizontal Force applied while carrying 10m,
Height descended in setting the child down
For full time, assuming that the total value of work is always expressed in terms of its symbol, it would be zero, since at first it performs the same work that is later complemented in a negative way.
