Question

1. draw: the sun’s gravitational pull on the earth the earth’s gravitational pull on the sun
2. why do you think the earth moves, but the sun does not move?
3. return to your pictures in questions 2 and add arrows to show the force of gravity. label them with \gravity force\.

gravity and orbits activity
page 2

Explanation:

1. For the Sun's gravitational pull on the Earth, draw an arrow starting from the Earth and pointing towards the Sun. For the Earth's gravitational pull on the Sun, draw an arrow starting from the Sun and pointing towards the Earth. According to Newton's third - law, these forces are equal in magnitude and opposite in direction.
2. The Earth moves around the Sun because its mass is much smaller than the Sun's. The Sun has a much larger mass, so the acceleration it experiences due to the Earth's gravitational pull is very small compared to the acceleration the Earth experiences due to the Sun's gravitational pull. In fact, the Sun also moves slightly due to the Earth's pull, but its motion is negligible compared to the Earth's orbit around it.
3. Without seeing the pictures in Question 2, in general, for any two objects, draw an arrow between them, pointing from one object to the other to represent the gravitational force, and label it "Gravity Force".

Answer:

1. Draw arrows as described above.
2. The Earth moves as its mass is much smaller than the Sun's, resulting in a larger acceleration for the Earth under their mutual gravitational force. The Sun also moves slightly but negligibly compared to the Earth's motion.
3. Add appropriate arrows and labels to the pictures in Question 2 as described above.