In an experiment to determine the acceleration due to gravity, one student drops a tennis ball out of the school's third floor window. Another student starts a timer when the first student lets go and stops the timer when the ball hits the ground. They conduct the experiment once and record the data. Is this a valid experiment, why or why not?

describe matter a earth

a small container that holds a source of energy a solar cell that captures light energy and converts it into electricity a voltaic cell that uses the oxidation of a fuel to produce electricity

explanation:

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.

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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.  

b. is the answer hoped i