The International Space Station (ISS) has a mass of about 441,000 kg and orbits at a height of about 4.0 x 105 meters above the surface of Earth. If the average U.S. household uses about 40 billion joules (4.0 x 1010 J) of energy in a year, how many households could be powered for a year by the gravitational potential energy stored in the ISS? The height of the ISS above Earth's surface is small enough that you can still use mgh as a reasonable approximation to calculate the gravitational potential energy.

Since 1995, hundreds of extrasolar planets have been discovered. There is the exciting possibility that there is life on one or more of these planets. To support life similar to that on the Earth, the planet must have liquid water. For an Earth-like planet orbiting a star like the Sun, this requirement means that the planet must be within a habitable zone of 0.9 AU to 1.4 AU from the star. The semimajor axis of an extrasolar planet is inferred from its period. What range in periods corresponds to the habitable zone for an Earth-like Planet orbiting a Sun-like star?

The International Space Station (ISS) has a mass of about 441,000 kg and orbits at a height of about 4.0 x 105 meters above the surface of Earth.  If the average U.S. household uses about 40 billion joules (4.0 x 1010 J) of energy in a year, how many households could be powered for a year by the gravitational potential energy stored in the ISS?

As it orbits Earth, the 11,000-kg Hubble Space Telescope travels at a speed of 7,900 m/s and is 560,000 m above Earth's surface. What is its potential energy? (Assume that the Hubble Space Telescope is close enough to Earth that its acceleration due to gravity is g = 9.8 m/s2. Take the potential energy relative to the surface of Earth.)