When the water balance force F acts on the object with mass m, it means to move the displacement l along the direction of the force on a smooth horizontal plane. The work done by the constant force is W1, and then use the constant force Then the force is applied to the mass m (m)

When the water balance force F acts on the object with mass m, it means to move the displacement l along the direction of the force on a smooth horizontal plane. The work done by the constant force is W1, and then use the constant force Then the force is applied to the mass m (m)

If the work done twice is equal, it is f * L