Gravity itself is not a particle; it is a force. A force can't have mass.
There are theories that state that there is a particle responsible for gravity, but it has not been conclusively observed, and the effect it has on matter wouldn't have a mass.
Here's another way of looking at it. What is the mass of you opening the door?
There is no answer. Mass simply doesn't apply in the scenario; forces do, however.
The weight of a football is a non-example of atomic mass. Atomic mass refers to the average mass of an atom of a chemical element, while the weight of a football is a measure of the force of gravity acting on the football due to its mass.
13
Atomic no.=no. of protons Atomic mass=no. of protons+no. of neutrons Hence, atomic mass is greater
The atomic mass is the mass of a molecule, atomic particle or sub-atomic particle.
Atomic mass
The atomic mass (or weight) of silver is 107.8682 amu (atomic mass units)
The atomic mass number of aluminum is 27. The atomic mass of aluminum is 26.98115386
Cobalt has an atomic mass of 58.933195(5) while nickel has an atomic mass of 58.6934(4). Nickel has the lower atomic mass.
The atomic mass of arsenic is approximately 74.92 atomic mass units.
The atomic mass of potassium is approximately 39.10 atomic mass units.
== == Atomic Mass: 54.93805 amu
Sulfur has an atomic mass of approximately 32.06 atomic mass units.