# gravity in the solar system

## the role of gravity

Isaac Newton first described gravity as the force that causes objects to fall to the ground and also the force that keeps the Moon circling Earth instead of flying off into space in a straight line. Newton defined the Universal Law of Gravitation, which states that a force of attraction, called gravity, exists between all objects in the universe (Figure from each other. The greater the objects mass, the greater the force of attraction; in addition, the greater the distance between objects, the smaller the force of attraction. The distance between the Sun and each of its planets is very large, but the Sun and each of the planets are also very large. Gravity keeps each planet orbiting the Sun because the star and its planets are very large objects. The force of gravity also holds moons in orbit around planets. The force of gravity exists between all objects in the universe; the strength of the force depends on the mass of the objects and the distance between them. Click image to the left or use the URL below. URL:

## instructional diagrams

No diagram descriptions associated with this lesson

## questions

gravitational force depends on ___.

``````a) the mass of the objects

b) the distance of the objects

c) the volume of the objects

-->  d) both a and b
``````

the greater an objects mass, the greater the force of attraction.

``````-->  a) true

b) false
``````

the farther the distance between two objects, the greater the attraction.

``````a) true

-->  b) false
``````

this famous scientist was first to discover the principal of gravity.

``````a) galileo galilei

-->  b) sir isaac newton

c) albert einstein

d) erwin schrodinger
``````

which of these planets experiences the weakest gravitational pull to the sun?

``````a) venus

b) mercury

c) jupiter

-->  d) neptune
``````

which of these planets experiences the strongest gravitational pull from the sun?

``````a) earth

-->  b) mercury

c) mars

d) venus
``````

which of the planets in our solar system has the greatest gravitational pull?

``````a) neptune

b) uranus

c) saturn

-->  d) jupiter
``````

if you are on the top of a mountain and drop an apple, it will fall to the ground, even though the apple is gravitationally attracted to you. why?

``````-->  a) earth is larger and has a much stronger gravitational pull.

b) apples always fall down.

c) centrifugal forces pull the apple to the earth and that is stronger than your gravitational pull.

d) none of these.
``````

the planets are all really far from the sun, but they continue to orbit the star because

``````-->  a) the sun and the planets are all really large.

b) the suns gravity increases with distance from it.

c) centrifugal forces continue to operate even when two objects are too far for gravity.

d) space has fibers that keep the planets orbiting the sun.
``````

## diagram questions

No diagram questions associated with this lesson