-- If there are only <em>10</em> elements in the universe that can make compound molecules, and a compound molecule can be formed by combining 1, 2, 3, or 4 different elements, then that's already the possibility of at least 400 different molecules.
-- There are many more than 10 elements that can combine to form compound molecules.
-- Every single "<em>organic</em>" molecule, of which there are thousands, is the combination of <em>carbon</em> with other elements.
-- Most all of the substances that can be distilled out of oil, including the paraffin waxes, the alcohols, gasoline, kerosene, butane, propane, octane, and natural gas, are made of just carbon, hydrogen, and oxygen, only with different numbers of each one.
-- Plastics, drugs, rubber, and DNA are examples of molecules that are made of <em>hundreds</em> of atoms.
I attached a free body diagram for a better understanding of this problem.
We start making summation of Moments in A,



Then we make a summation of Forces in Y,



At the end we calculate the angle with the sin.


Even though the object is weightless, it would need inertia, I.e, you pushing it or any form of transportation. So you would still have to push that 500kg to just keep it moving in space. Say if it were a planet with less gravitational force, it would be weightless.
1. For the first one if it doesn't shatter then it is hard.
2. We sould consider that room temperature is usuall<span>y from 18°C (64°F) to 23°C (73°F) and since the melting point of the substance is 40˚C the substance is liquid, because is melting point not an evaporation point it just melts from solid to liquid.
3. Well, in this one we have to consider that a chemical change it change the thing completely. So in this case is baking a cake because the products make the cake stop being them self and created something else.
4. It tends to have low reactivity. This is because viscosity means something like honey very sticky<span> ,</span> density is how hard it is and lastly the conductivity I would believe is to pass electricity or current.
5. It is a physical change because the evaporated water transforms again into water and then fall as rain, snow or ice.
Hope it helped <3</span>