An object that has a weight of 15 N on Earth is taken to a planet where it has a weight of 3.0 N.
The planet has no atmosphere. Which line in the table correctly shows the mass of the object on the planet, and the kinetic energy it gains after falling from rest near the surface of the planet through a vertical distance of 10 m?

Answer:

23) E

No matter which planet you take the object to, the MASS will remain the same as it is on Earth.
Mass of object on Earth = 15N/10 = 1.5 kg

Kinetic energy = Potential energy
Potential energy = mass (1.5kg) x gravitational acceleration (?) x height (10m)

Gravity is 5 times (15N/3N) weaker on the planet. Therefore the acceleration must also be 5 times weaker. Gravitational acceleration = 10/5 = 2 N/kg

Potential energy = 1.5 x 2 x 10 = 30J
Kinetic energy = 30J

The answer is therefore row E.