B. A current in charges change direction
Explanation: an electric current that reverses its direction many times a second at regular intervals, typically used in power supplies.
The formula of mechanical advantage in this situation is:
MA = Input Force ÷ Output Force
The input force is the 30N applied to a screwdriver while the output force is the 75N force to the lid.
So,
MA = 30N/75N
MA = 0.40
Hence the mechanical advantage of the screwdriver is 0.40.
Mg3(PO4)2 - the molar mass would be 262g/mol, which is 100%
Atomic mass of Mg is 24, since we have 3Mg we multiply by 3 and get a mass of 72
262 : 100% = 72 : x%
x = 72*100 / 262
x = 27.5%
And do that for every element — get the molar mass of P and multiply by 2, use a ratio, and get the molar mass of O and multiply by 8 and use ratios :)
there are 8 planets in our solar system 1.Mercury 2.venus 3.earth 4.mars 5.jupiter 6.saturn 7.uranus 8. neptune
Atoms have no electric charge because the protons and electrons "cancel out" each others charges. Neutrons have no charge. What is the atomic number of an element? The atomic number is the number of protons in the atom's nucleus.
Hope this helps have a great day :)
