The gravitational force causesa. Tidesb. Motion of moonc. None of themd. Both a n b

Question Analysis

The question asks about the effects of gravitational force. It provides several options to consider regarding what the gravitational force causes: tides, the motion of the moon, both, or neither.

Relevant Concepts

1. Gravitational Force and Tides: The gravitational pull of the moon (and the sun to a lesser extent) on Earth is responsible for the occurrence of tides. This force causes the water levels to rise and fall in the oceans.

2. Gravitational Force and the Motion of the Moon: The gravitational force also plays a crucial role in keeping the moon in orbit around the Earth. The moon's motion is a direct result of this gravitational interaction.

Analysis

1. Tides (Option a): Caused by the gravitational pull of the moon and sun on Earth.
2. Motion of the Moon (Option b): The moon orbits the Earth due to gravitational attraction.
3. None of them (Option c): Incorrect, as both tides and the moon's motion are influenced by gravitational forces.
4. Both a and b (Option d): Correct, as gravitational force is responsible for both phenomena.

Verify and Summarize

Both options a and b correctly reflect the effects of gravitational force. Therefore, option d ("Both a and b") is the most appropriate answer.

Final Answer

d. Both a and b