A student practicing for a track meet ran 300 meters in 30 seconds. what was her average speed?

Explanation:

Her average speed can be found by using the formula

d is the distance

t is the time taken

From the question we have

We have the final answer as

Hope this helps you

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.