Concept explainers
(a)
Moon’s gravitational field at the side of Earth which is facing Moon.
(a)
Answer to Problem 55PQ
Moon’s gravitational field at the side of Earth facing Moon is
Explanation of Solution
Write the equation to find the gravitational field due to Moon at a distance of Moon-Earth distance minus radius of Earth.
Here,
Write the expression to find
Here,
Use the expression for
Conclusion
Substitute
Therefore, Moon’s gravitational field at the side of Earth facing Moon is
(b)
Moon’s gravitational field at the side of Earth facing away from Moon.
(b)
Answer to Problem 55PQ
Moon’s gravitational field at the side of Earth facing away from Moon is
Explanation of Solution
Write the equation to find the gravitational field due to Moon at a distance of Moon-Earth distance plus radius of Earth.
Write the expression for
Substitute the expression for
Conclusion:
Substitute
Therefore, Moon’s gravitational field at the side of Earth facing away Moon is
(c)
The gravitational field of Moon at the center of Earth.
(c)
Answer to Problem 55PQ
Moon’s gravitational field at the center of Earth is
Explanation of Solution
Write the equation to find the gravitational field due to Moon.
Conclusion:
Substitute
Therefore, Moon’s gravitational field at center of Earth is
(d)
Sketch Earth and include the three vectors from parts (a) through (c).
(d)
Answer to Problem 55PQ
Sketch of Earth and the three vectors from parts (a) through (c) is shown in Figure 1.
Explanation of Solution
Figure 1 shows the sketch of the Earth and the magnitude and direction of the gravitational field vectors found in part (a), (b) and (c).
Conclusion:
Therefore, Sketch of Earth and the three vectors from parts a through c is shown in Figure 1.
(e)
The reason why there are two tides a day on most places on Earth due to Moon.
(e)
Answer to Problem 55PQ
There are two tides a day on most places on Earth due to Moon because the force is larger on bodies of water closer to Moon and smaller on bodies of water on far side of Earth.
Explanation of Solution
Figure below shows the Earth and Moon. High tides and low tides on either side of Earth are due to the lunar activity on Earth. The gravitational pull by Moon on Earth causes high tide and low tide.
The force of Moon is large at water bodies which are close to Moon and lowest on water bodies which are far away. Thus the amplitude or strength of tides is dependent on the distance of the water body and Moon. This is the reason for two types of tides on Earth.
Conclusion:
Therefore, there are two tides a day on most places on Earth due to Moon because the force is larger on bodies of water closer to Moon and smaller on bodies of water on far side of Earth.
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Chapter 7 Solutions
Physics for Scientists and Engineers: Foundations and Connections
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