The atomic number gives you the number of protons element x has. Since the mass of protons and neutrons are almost similar(around 1 amu), the mass number can be thought of as the sum of protons and neutrons. so if element x whose atomic number is 40 has a mass number of 82, then we know that 42 of those must be neutrons.
I think ans is experimentation because logic and writing is important in philosophy
I don’t see any answer choice but the best way is asking questions about the natural phenomenon, making hypothesis, and predicting the consequences in the hypothesis.
Power = work done/time. Work done by gravity = mgh = 45x9.8x3.2 = 1411.2J. Therefore, power = 1411.2/2 = 705.6 ~ 706W.