Tides on Earth occur because of the gravitational force between the Earth, the Moon, and the Sun. Because gravitational force decreases with increasing distance, the force of the Moon's gravity is less on the side of Earth facing away from the Moon than on the side of Earth facing the Moon. The Sun also causes tides, but the Sun's effect on tides is less than that of the Moon. The effect of their combined gravitational forces is to try to squeeze Earth into an ellipse. However, the Earth's crust is rigid and does not easily deform. The water in the ocean flows and piles up to create high tides. The figure provided shows the tidal bulges created by the gravitational forces of the Moon and Sun.

Question

Tides on Earth occur because of the gravitational force between the Earth, the Moon, and the Sun. Because gravitational force decreases with increasing distance, the force of the Moon's gravity is less on the side of Earth facing away from the Moon than on the side of Earth facing the Moon. The Sun also causes tides, but the Sun's effect on tides is less than that of the Moon. The effect of their combined gravitational forces is to try to squeeze Earth into an ellipse. However, the Earth's crust is rigid and does not easily deform. The water in the ocean flows and piles up to create high tides. The figure provided shows the tidal bulges created by the gravitational forces of the Moon and Sun.

2
A person is fishing in a bay when low tide occurs, stranding the person in the boat. Approximately how long will this person have to sit in the boat until the next high tide occurs and the person can leave the bay?
A.
16 hours
B.
24 hours
C.
6 hours
D.
3 hours

Answer 1

B. 24 hours

Tides typically go through two high tides and two low tides in a 24-hour period. So, after low tide, the person would have to wait roughly 12 hours for the next high tide, and another 12 hours for the tide to go from high tide to low tide again. This would total 24 hours.