Universal Law of Gravitation
Learning Newton's law describing gravitational attraction between objects.
Core concept
This universal force explains why the Moon orbits the Earth (Earth's gravity constantly pulls the Moon towards it, creating a curved orbital path rather than a straight line), why objects fall towards the ground, and why planets orbit the Sun. Gravitational force also explains ocean tides, caused primarily by the Moon's gravitational pull creating bulges in Earth's oceans on the side facing the Moon and, to a lesser extent, on the opposite side.
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• Newton's law of gravitation: force is proportional to the product of masses, inversely proportional to distance squared.
• Gravitational force explains why the Moon orbits Earth, and why objects fall.
• Gravitational force weakens with distance but never reaches exactly zero.
• Ocean tides are caused primarily by the Moon's gravitational pull on Earth's oceans.