Question

How much force is needed to lift a 25-kg mass?

Answer 1

The force needed to lift the object must be (at least) equal to the weight of the object itself. In fact, the weight W of the object pushes downward, while the force we apply, F, pushes upward. The weight of the object is
where
`m=25 kg` is the mass and
`g=9.81 m/s^2` is the gravitational acceleration. Substituting, we have

`W=mg=(25 kg)(9.81 m/s^2)=245.3 N`
And therefore, the force F we have to apply must be at least equal to this value, in order to lift the object.