Problem: An unmanned spacecraft is in a circular orbit around the moon, observing the lunar surface from an altitude of 55.0km. To the dismay of scientists on earth, an electrical fault causes an on-board thruster to fire, decreasing the speed of the spacecraft by 15 m/s. If nothing is done to correct its orbit,
Part A- with what speed (in km/h) will the spacecraft crash into the lunar surface?
Please use great detail in explaining the solution. Thanks.