Question Detail
Question
An object on the surface of the moon has a velocity of 10 m/s at the height of 120 m above the moon's surface. Taking the moon's gravitational acceleration as 1.6 m/s², with what speed does the object strike the moon?
Correct Answer
Option B is the correct answer.
Detailed Explanation
Use v² = u² + 2as, with u = 10 m/s (assuming downward? The problem doesn't specify direction, but if it's at a height and moving, likely downward. If upward, we need to know. Typically, if it's moving upward, it would go up and then down. But given the numbers, let's assume it's moving downward. Then v² = 10² + 2×1.6×120 = 100 + 384 = 484, so v = √484 = 22 m/s. If it were moving upward, it would first go up, then come down, and the speed at impact would be the same as if it were dropped from a higher point, but the calculation would be different. Given the options, 22 m/s is there.
Hint
Use the kinematic equation v² = u² + 2gh, assuming the initial velocity is downward.