<u>Answer:</u>
The modern atomic theory has given by "John Dalton and framed postulates".
<u>Explanation:</u>
The fundamental role of atoms in chemistry is established by the modern theory of atoms mentioned in 1808 for the first time by an English scientist named John Dalton. This consists of three sections such as all matter is composed of atoms, atoms of the same element are the same while atoms of different elements are different, atoms combine to form compounds in full-number ratios.
The unique characteristic of the "number of protons" is that all atoms of the same compound share. While the atoms of the same element i.e having a similar number of protons can have different numbers of neutrons and such elements are called isotopes.
Answer:
Potential energy is
Explanation:
Given situation is shown in figure 1
In order to calculate the potential energy at the moment block started moving we first have to calculate the net force acting on the block. For this consider figure 2
<h3>Forces acting in vertical direction:</h3>
Normal force Fn acting on block is in upward direction which is balanced by horizontal component of weight of block acting in opposite direction.
<h3>Forces acting in horizontal direction:</h3>
Tension in string is equal and opposite to frictional force and and vertical component of weight as show in figure 2
Frictional force is:
From (1)
(2) becomes then
If spring is not accelerating then tension in rope must be equal spring force i.e
Then (2) becomes
Potential energy is given as