<span>When a force is applied to an object for an amount of time, it is known as Impulse.</span>
Special relativity led the path for general relativity; special relativity is in a sense a special application of the rules of general relativity. While general relativity is in position to tackle all of these problems, special relativity can tackle only problems in inertial frames. Inertial frame means that the frame of reference is inot accelerating. So, we disqualify answers A and D. However, remember that moving in a circle means that there is an acceleration, the centrifugal one, even if the speed does not change. Hence C is also incorrect.
The correct answer is B, since if there is no change in velocity, the frame does not accelerate and it is inertial.
Solid carbon is an element in its solid state, not a mixture.
Carbon-dioxide gas is a compound in its gaseous state, not a mixture.
Liquid copper is an element in its liquid state, not a compound.
Copper will never dissolve in water, so copper in water is a mixture.
The number of protons tells you what element an atom is. Just knowing the number of neutrons/mass number does not tell you what element an atom is, since atoms of the same element can have different mass numbers. But all atoms with the same number of protons, are also always of the same element.
Hence, we can identify an atom by the number of protons it has
