Satellite Motion 1

Satellites stay in orbit because of a lack of gravity.

• True

• False

Answer explanation

If there was a lack of gravity, the satellite would fly away, not be in orbit.

Tags

NGSS.MS-PS2-4

NGSS.MS-ESS1-2

The force of gravity in low Earth orbit is still about ____ the strength of what it is on Earth's surface

• 0%

• 25%

• 90%

• 110%

Answer explanation

From Wikipedia:

"In fact, at an altitude of 400 kilometers (250 mi), equivalent to a typical orbit of the ISS, gravity is still nearly 90% as strong as at the Earth's surface."

This is because that 250 miles is small compared to the whole radius of the Earth so the force of gravity is not diminished much.

Tags

NGSS.HS-PS2-4

Orbiting and weightlessness are because of a lack of gravity.

• True

• False

Answer explanation

Gravity is necessary for both.

Tags

NGSS.MS-ESS1-2

Being outside of Earth's atmosphere (being in space) makes the force of gravity much less.

• True

• False

Answer explanation

Compared to the whole planet, the atmosphere isn't very thick so being outside the atmosphere doesn't put you much farther from the center of the Earth so the force of gravity isn't changed much.

Tags

NGSS.MS-PS2-4

Weightlessness is a condition of ____.

• having no gravity

• being in freefall

• accelerating upward

Answer explanation

Weightlessness is not the absence of gravity but the absence of a supporting force because of free fall.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-5

Satellites in orbit around some planet are constantly falling around the planet.

• True

• False

Answer explanation

Satellites are always falling but go sideways enough so that the curvature of the Earth (or other planetary body) prevents them from hitting. They are falling around the Earth.

Tags

NGSS.MS-PS2-4

NGSS.MS-ESS1-2

How fast must a satellite be going in order to be in orbit close to Earth's surface?

• About 8000 m/s which is about 17,800 mi/hr

• Anything under 8000 m/s

• It depends upon how heavy the satellite is.

Answer explanation

That also works out to be almost 5 miles/second. Really fast.

Tags

NGSS.MS-PS3-1

A satellite is any object that is orbiting the earth, sun or other massive body.

• True

• False

Satellites can be man-made.

• True

• False

Satellites can be naturally occurring.

• True

• False

Answer explanation

Any moon would be an example that and Earth and all the other planets are satellites of our sun.

Tags

NGSS.MS-PS2-4