Chapter 16, Problem 1QR

To determine

The reason for the greater tidal effect on Earth due to Moon as compared to the Sun.

Answer to Problem 1QR

Moon has a greater tidal effect on Earth than the Sun because the distance between the Moon and Earth is small. The distance is inversely proportional to the tidal effect. Therefore, small distance relates to the greater tidal effect of the Moon on the Earth

Explanation of Solution

The gravitational system of Earth, Moon and Sun, and their interaction generates the tidal energy. The tidal force is caused by the difference in gravitational force. It is inversely proportional to the cube of the distance.

This can be explained by Newton’s law of gravity. It states that the two bodies attract each other when the force is directly proportional to the product of the masses and inversely proportional to the square of the distance between the objects. It is written as:

$g\left(gravity\right)=\frac{G{m}_1{m}_2}{d^2}$

Where g is gravity, G is gravitational constant, $m_1$ and $m_2$ are the masses of objects, and d is the distance between objects.

The distance between the Moon and Earth is very less as compared to the distance between the Moon and the Sun. Due to the less distance between the Moon and Earth, the tidal force is large. Thus, the role of Moon in causing tides on Earth is more than the Sun and the tidal effect of Moon on Earth is larger as compared to the Sun.