Answer:
C. 1) No Change (4 sec) 2) 5.7 sec 3) 2.8 sec 4) No Change (4 sec)
Explanation:
Given that:
Period (T) = 4 s
1) If the mass is doubled.
The period of a pendulum is given by the formula:
where L is the length and g is the acceleration due to gravity.
From the formula, the period does not depend on the mass of the spring therefore if the mass is doubled the period does not change.
2) The string length is doubled
Given that:

if the length is doubled, the new spring length is 2L. Therefore the new period (T1) is given as:

3) The string length is halved
Given that:

if the length is halved, the new spring length is L/2. Therefore the new period (T1) is given as:

4) The amplitude is halved
From the formula, the period does not depend on the amplitude therefore if the amplitude is halved the period does not change.
The answer to this question is A.
According to given condition there is no height(m) given from roof of building to the ground, there height given 18 m at a point above the ground. So, h=18m , mass=3kg , g=9.8m/s2 P.E=mgh P.E=(3)(9.8)(18) P.E=529J
<span>Describe the relationship of attractive forces between molecules and the ability of a solvent to dissolve a substance. Solvents can dissolve a substance only if the attraction of the solvent molecules is greater than the attraction between the molecules of the substance.</span>
1. Avogadro's hypothesis. Avogadro hypothesized that equal volumes of all gases (at the same pressure) will have the same number of molecules. From PV=nRT, we know that one mole of gas takes up 22.4 L
2. Mass number. The mass number is the sum of the protons and neutrons in the nucleus so Carbon 12 has an atomic number of 6 which indicates 6 protons, and a mass number of 12 so 12-6 = 6 neutrons.
3. Avogadro's number. Avogadro's number is the number of units in one mole of any substance, which has been defined as 6.02 x10^23
4. Isotopes are the different forms of a single element. They differ in neutrons. One example is Hydrogen which has three isotopes Protium, Deuterium, and Tritium.
5. Atomic mass. The mass of the atom is equal to the sum of the protons and the neutrons as electrons are so small their mass is negligible. This is not exactly the same as the mass number because this number takes into account the different isotopes
6. mole A mole has the same number of entities as 12 grams of carbon 12, it is expressed by Avogadro's number so 1 mole = 6.02 x10^23 atoms or molecules, etc
7. molar mass- the amount that one mole of substance weighs. For carbon 12, 12 grams has one mole of atoms by definition. So for carbon 12, the molar mass is 12 g/mol