Problem 13.63 The moon's radius is 1738 km. The magnitude of the acceleration due to gravity of the moon at a distances from the center of the moon is 4.89 1012 $2 m/s. Suppose that a spacecraft is launched straight up from the moon's surface with a velocity of 2000 m/s. (a) What will the magnitude of its velocity be when it is 1000 km above the surface of the moon? (b) What maximum height above the moon's surface will it reach?