Unit 2, Lesson 4: Gravity in the Universe

The moon revolves around Earth. The moon travels at a speed of about 1 km/s. What keeps the moon in orbit around Earth?

• gravity

• magnetism

• ocean tides

• nuclear tides

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NGSS.MS-ESS1-1

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Two objects have a certain gravitational force between them. What would happen if the mass of one of the objects suddenly increased?

• The mass of the other object would increase.

• The distance between the objects would increase.

• The gravitational force of the objects would remain constant.

• The gravitational force between the two objects would increase.

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NGSS.MS-PS2-4

Why are Earth, other solar system planets, and most planetary objects spherical?

• force of gravity acting evenly in all directions around the center of mass

• erosion made by asteroids hitting the objects' surface after the object's formation

• heat received from the sun melting the object's surface at the time of formation

• pressure of atmosphere acting evenly in all directions on the object's surface

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NGSS.MS-ESS1-2

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Planets are held in their orbit because of their large sizes as well as a certain force that acts over a distance. Which force is responsible for acting on the planets?

• nuclear force

• electrical force

• magnetic force

• gravitational force

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NGSS.MS-ESS1-2

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Objects A and B have the same mass but are located at different distances from the surface of Mars. Which statement explains how the gravitational field affects the objects shown in the model.

• Only object B will be pulled toward Mars because object A is too far away to be affected by the field.

• Object A and object B will be affected equally ty the gravitational field because the field lines indicate a uniform field.

• Object B will be more affected by the gravitational field because the field lines are closer together near the surface of Mars.

• Object A will be more affected ty the gravitational field because the field lines are farther apart farther from the surface of Mars.

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NGSS.MS-ESS1-2

NGSS.MS-PS2-4

The diagram shows a satellite in orbit around Earth. It is orbiting in the direction shown and is pulled toward Earth by gravity. What would happen if Earth's gravity suddenly disappeared?

• The satellite would fall to Earth.

• The satellite would stop moving.

• The satellite would continue to orbit Earth.

• The satellite would move into space in a straight line.

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NGSS.MS-ESS1-2

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Use the diagram to answer the question. The dotted lines in the picture show orbital paths of objects. Which statement is true about all of the orbits shown?

• All objects move in circular orbits.

• The size of an object determines the size of its orbit.

• The force of gravity is what holds each object in its orbit.

• The size of both an object and the object it orbits are equal.

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NGSS.MS-ESS1-2

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Which object exerts the greatest gravitational pull in the diagram?

• the star

• Planet 1

• Planet 3

• Planet 5

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NGSS.MS-ESS1-2

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Which one of Newton's Laws (first, second, third) explains the following observation:

Asteroids continue to move in an elliptical orbit in a belt around the star

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NGSS.MS-ESS1-2

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Newton's laws of motion and of universal gravitation apply to the star and planets pictured here. Suppose Planet 3 is similar to Earth. Check each of the following TRUE statements.

• The weight of an object measured on Planet 3 is a result of gravity.

• Because of gravity, Planet 3, which is smaller than the star, remains in orbit around the star.

• Small objects near Planet 3 experience much less acceleration the closer they get to the surface of the planet.

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NGSS.MS-ESS1-2

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