Answer:
The correct answer is option A: they are isotopes.
Explanation:
From atom X we know that the number of protons is 7 and the number of neutrons is 7 and from atom Z we know that the number of protons is 7 and the number of neutrons is 8.
Since the number of protons of atom X and atom Z is the same, we have that atom X and atom Z is the same element. The difference in the number of neutrons tells us that atom X and atom Z are isotopes. Remember that an isotope is one element that has atoms with different numbers of neutrons.
The mass number is given by:
Where <em>n</em> is the number of neutrons and <em>p </em>is the number of protons.
For atom X and atom Z we have:
Hence, they have a different mass number.
We know that the element with 7 protons is nitrogen. The first isotope is 
and the second isotope is 
. Both isotopes are stables (they are not radioactive).
Therefore, the correct answer is option A: they are isotopes.
I hope it helps you!
Answer:
<em>b. Observe the radio waves coming from all dark matter; from the strength of the radio waves from each cluster, estimate the amount of dark matter needed to produce them.</em>
<em></em>
Explanation:
The universe is thought to be made up of 85% dark matters. <em>Dark matter is called dark because it does not appear to interact with the electromagnetic field, which means it doesn't absorb, reflect or emit electromagnetic radiation, and is therefore difficult to detect. This means that option b is wrong since radio wave is an electromagnetic wave</em>. Dark matter is a form of matter that makes up about a quarter of the total mass–energy density of the universe. Dark matter was theorized due a variety of astrophysical observations and gravitational effects that cannot be explained by accepted theories of gravity unless there were more matter in the universe than can be seen.
Answer:mile
Explanation: heres a hint think aboyt the distance between your house to school
Answer:
the acceleration is 130.3m/s²
Explanation:
Given data
Force F= 18.9N
Mass of ball m= 0.145kg
Acceleration a=?
Applying the Newton's second law of motion
"The rate of change of momentum of a body is proportional to the external force".
F=ma
a= F/m
a= 18.9/0.142
a= 130.3m/s²
At the same time, however, you get less detail or less precision in a chart or graph than you do in the table. Imagine the difference between a table of sales figures for a ten-year period and a line graph for that same data. You get a better sense of the overall trend in the graph but not the precise dollar amount.
