1. What did Newton conclude about the force that pulls apples to the ground and the force that holds the moon in orbit?
2. What does the very small value of the gravitational constant G (in standard units) tell us about the strength of gravitational forces?
3. We can think of a force field as a kind of extended aura that surrounds a body, spreading its influence to affect things. As later chapters will show, an electric field affects electric charges, and a magnetic field affects magnetic poles. What does a gravitational field affect? (Select all that apply.)
(charge, magnetism, mass or none of these)
4. Which is correct -- to say that a distant rocket interacts with the mass of the Earth, or to say that it interacts with the gravitational field of the Earth? (Select all that apply.)
(distant rocket interacts with Earth's mass, both of these, or distant rocket interacts with Earth's gravitational field)
The answer to question 3 is mass, but I don't know any more of them.
1. Newton concluded that the force that pulls apples to the ground and the force that holds the moon in orbit are both due to the same fundamental force of gravity. He formulated the law of universal gravitation, which states that every object in the universe attracts every other object with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
2. The very small value of the gravitational constant G indicates that gravitational forces are significantly weaker compared to other fundamental forces such as electromagnetic forces. It tells us that gravitational forces between objects are relatively weak, which is why we do not notice them in our everyday lives unless the objects involved have a very large mass, such as planets or stars.
3. A gravitational field affects mass. Unlike electric and magnetic fields, which have specific charges and magnetic poles as their sources, a gravitational field does not have a specific source. It influences all objects with mass, including particles, planets, stars, and any other massive objects in the universe. So the correct answer is "mass."
4. It is more accurate to say that a distant rocket interacts with the gravitational field of the Earth. The concept of mass creates a gravitational field around any object with mass. When a rocket is distant from the Earth, its interaction with the Earth is dominated by the gravitational field created by the Earth's mass. So the correct answer is "distant rocket interacts with Earth's gravitational field."