Answer:
C. The number of protons.
Explanation:
All atoms of mercury will remain the same while different isotopes may have different number of neutrons.
For example, mercury has 80 protons, correlating with its atomic number. However, the number of protons, neutrons, and electrons could vary between each atom. If there are 80 protons, then there has to be 80 electrons. This means that the protons have to be the same in order to apply to all atoms of mercury
Momentum and inertia,
Momentum=P. P=MV. M=mass and V=velocity. Mass is related to inertia so inertia=F. F=MA. A=acceleration.
Answer:
False
Explanation:
The net force is equal to the applied force minus the force of friction. It is possible for friction to act in the same direction as an applied force, but that would mean there would have to be more than two forces acting on the object.
Answer:

Explanation:
As per Kepler's III law we know that time period of revolution of satellite or planet is given by the formula

now for the time period of moon around the earth we can say

here we know that


= mass of earth
Now if the same formula is used for revolution of Earth around the sun

here we know that


= mass of Sun
now we have



