I attached the missing picture.
The force of seat acting on the child is a reaction the force of child pressing down on the seat. This is the third Newton's law. The force of a child pressing down the seat and the force of the seat pushing up on the child are the same.
There two forces acting on the child. The first one is the gravitational force and the second one is centrifugal force. In this example, the force of gravity is always pulling down, but centrifugal force always acts away from the center of circular motion.
Part AFor point A we have:

In this case, the forces are aligned, centrifugal is pointing up and gravitational is pulling down.
Part BAt the point, B situation is a bit more complicated. In this case force of gravity and centrifugal force are not aligned. We have to look at y components of this forces, y-axis, in this case, is just pointing upward.
Part CThe child will stay in place at point A when centrifugal force and force of gravity are in balance:
the answer is spiral galaxies
<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.
UTC is generally adopted as the local time at Prime Meridian (PM).
<h3>What is UTC?</h3>
UTC is an abbreviation for Coordinated Universal Time and it can be defined as a local time standard by which all clocks, time and time zones are regulated around the world.
This ultimately implies that, Coordinated Universal Time (UTC) is generally adopted as the local time at Prime Meridian (PM) because it nominally reflects mean solar time.
Read more on UTC here: brainly.com/question/14333785
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