Exam 4: Gravity and Orbits

How fast is the Moon moving as it orbits the Earth? For reference, the Moon's orbit is approximately circular with a radius equal to 400,000 km, and the Moon's orbital period is 27 days.

Figure 2 -According to Figure 2, when Earth is in between the Moon and the Sun, _________ tides occur.

Explain the difference between being weightless and being in free fall.

Figure 2 -According to Figure 2, when the Moon is in between Earth and the Sun, _________ tides occur.

How does the force of gravity between the Sun and Jupiter compare to the gravitational force between the Sun and the Earth? Note that the semimajor axis of Jupiter's orbit is 5.2 AU, and Jupiter's mass is 320 times the mass of the Earth.

The International Space Station orbits at an altitude of 400 km above the Earth's surface. Assuming it is in a stable circular orbit, what is its velocity? For reference, the Earth's radius is 6,400 km, and Earth's mass is 6 * 10²⁴ kg and G = 6.7 * 10^-11 N m²/kg².

Tidal forces can affect:

An unbound orbit results when a satellite has a velocity greater than the escape velocity.

Which of the following properties of an astronaut changes when he or she is standing on the Moon, relative to when the astronaut is standing on Earth?

Titan, the largest moon of Saturn, has an orbital period of 16 days and a semimajor axis of 1.2 *10⁹ m. Based on this information, what is Saturn's mass? For reference, the Earth's mass is 6 * 10²⁴ kg.

Moons that wander inside of a planet's Roche limit can be torn apart due to tidal forces.

The Moon always keeps the same face toward Earth because of:

What is the escape velocity from a large asteroid if its mass is 6 * 10²¹ kg and its radius is 2,400 km?

-According to the progression shown in the figure above, if the distance between two objects is increased to four times its original value, the gravitational force between the two objects would be _________ times its original value.

When the Sun and Moon are separated by 90 degrees in the sky, _________ tides occur on Earth when the strength of the tides are _________ than normal.

Assume that a planet just like Earth orbits the bright star named Sirius. If this Earth-like planet orbits with a semimajor axis of 1 AU and an orbital period of 7 months, what is the mass of Sirius?

If you measured the orbital period of the Moon and the distance between the Earth and the Moon then you could calculate:

Figure 1 -According to Figure 1, the approximate amount of time between a high tide and a low tide at a given location is:

_________ hypothesized that planetary motions could be explained by a force arising from the attraction between the mass of the planet and Sun that decreased with the square of the distance between them.

Explain what the Roche limit is and how it is related to rings around giant planets.