While hovering motionless 3.0 m above an asteroid, a small unmanned space-craft suddenly lost power and fell to the surface of the asteroid. It landed on an instrument mounted on the outside of the craft. From the instrument, scientists on Earth were able to determine the weight of the still intact craft. It weighed 120 N on the asteroid.
How much work was done (before the impact) on the space-craft by the asteroid as it fell 3.0 m ?