Problems
Problems

 1 The angular diameter and distance of the Moon are 31 minutes of arc and 384,400 km. Use the small angle equation to find the linear diameter of the Moon. 2 Suppose the Moon's rotation period were half as long as its orbital period about the Earth. How long would it take the Earth to complete one trip around the sky? (Hint: One way to find the answer is to sketch the position of an observer on the Moon throughout several lunar orbits.) 3 When flight controllers on Earth spoke to Apollo astronauts on the Moon, there was a noticeable time delay in the communications. How long does it take a radio signal to travel to the Moon and back? 4 What is the angular diameter of the Earth as seen from the Moon? 5 If the Earth's rotation continues to slow at its present rate, how long will it take for the day to lengthen by 1 hour? 6 If the month continues to lengthen at its present rate, how long will it take for the month to reach 47 days in length? 7 The Imbrium Basin is about 700 km in diameter. Approximately how large was the impacting body that produced the Imbrium Basin?