Newton's law of universal gravitation, says that every particle attracts every other particle in the universe with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
Or in simple words, every particle in the world attracts each other to themselves, but the particle with most mass would attract with more force compared to a particle with less mass.
(<u><em>Please consider leaving a rate, a thanks and, a crown would be really appreciated! Thank you!</em></u>)
Answer : Cat will reach tree first.
Explanation :
It is given that,
Total distance between dog and tree is 30 yards. The cat has 10 yards lead. So, the distance between cat and tree is 20 yards.
Speed of cat is 6 Yards/ sec.
Speed of dog is 8 Yards/sec.
speed of cat is, 
Now, speed of dog is, 
It is clear that, cat is taking less time as compared with dog. So, the cat will reach tree first.
The gravitational attractions are greatest be when the objects have large masses and they're closer together. Their sizes don't matter.
Answer:
An atom is the smallest unit of matter that retains all of the chemical properties of an element. Atoms combine to form molecules, which then interact to form solids, gases, or liquids. For example, water is composed of hydrogen and oxygen atoms that have combined to form water molecules. Many biological processes are devoted to breaking down molecules into their component atoms so they can be reassembled into a more useful molecule.
Atomic Particles
Atoms consist of three basic particles: protons, electrons, and neutrons. The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). The outermost regions of the atom are called electron shells and contain the electrons (negatively charged). Atoms have different properties based on the arrangement and number of their basic particles.
The hydrogen atom (H) contains only one proton, one electron, and no neutrons. This can be determined using the atomic number and the mass number of the element (see the concept on atomic numbers and mass numbers).
The only thing I can think of is if you have a thermos with cold or hot liquid and it is closed than it is an isolated energy system but if you take the lid off it would be an open energy system since it's losing its temperature.
