Final answer:
The ease of lifting an object on Earth is determined by the force of gravity, which is greater on objects with more mass, making heavier stones harder to lift than lighter ones. Therefore, the correct option is B
Step-by-step explanation:
The reason it is easier to lift a small stone but harder to lift a heavy one on the surface of Earth is because of the force of gravity. Objects with more mass experience a greater force of gravity, which makes them heavier and more difficult to lift. This force of gravity is what gives objects their weight.
It is important to understand that weight is the measure of the gravitational force between the object and Earth. This force is directly proportional to the mass of the object and the gravitational acceleration on Earth (9.80 m/s²). Hence, a heavier object with more mass will have a greater gravitational force acting on it, making it harder to lift.
Newton's Third Law also explains that when we lift an object, we exert a force on it, and it exerts an equal and opposite force on us. Therefore, lifting a heavier object requires more effort because you need to overcome a larger gravitational force.