BEST PRACTICE Using the Law of Universal Gravitation

Use the data for Mercury in the given table to find the speed of a satellite in orbit 265 km above Mercury’s surface.

Use the data for Mercury in the given table to find the period (in hours) of a satellite in orbit 265 km above Mercury’s surface. Express the answer in 3 significant figures. No need to write the unit.

The sun is considered to be a satellite of our galaxy, the Milky Way. The sun revolves around the center of the galaxy with a radius of 2.2 x 10²⁰ m. The period of one revolution is 2.5 x 10⁸ years. Find the mass of the galaxy.

• 1.0 x 10⁴¹ kg

• 3.2 x 10⁴⁰ kg

• 1.7 x 10¹⁶ kg

• 5.8x 10⁴ kg

The asteroid Ceres has a mass of 7 × 10²⁰ kg and a radius of 500 km. What is g on the surface (in m/s²)? Express the answer to 1 decimal place. No need to write the units.

The asteroid Ceres has a mass of 7 × 10²⁰ kg and a radius of 500 km. How much would an 85-kg astronaut weigh (in newtons) on Ceres? Express the answer to a whole number. No need to write the units.

Mars has about one-ninth of the mass of Earth. The figure shows satellite M, which orbits Mars with the same orbital radius as satellite E, which

orbits Earth. Which statement is true?

• The period of satellite M is greater than the period of satellite E.

• The period of satellite E is greater than the period of satellite M.

• The period of satellite M is equal to the period of satellite E.

• There is not enough information to make a conclusion about the satellites' periods.