Escape velocity is a measure of how fast an object must be moving to escape the gravitational pull of a planet or moon with no further thrust. The escape velocity for the moon is given approximately by the equation

V=5600 •(d/1000)^-(1/2) where v is the escape velocity in miles per hour and d is the distance from the center of the moon (in miles). If a lunar lander thrusts upwards until it reaches a distance of 16,000 miles from the center of the moon, about how fast must it be going to escape the moon’s gravity?