Accepted Answer
-- The weight of the box is (mass) x (acceleration of gravity) = (52 kg) x (9.81 m/s²) = 510 newtons (rounded) .-- The normal force of the desk pushing up on the underside of the box must beexactly the same 510 newtons (rounded). If the vertical forces acting on thebox were not balanced, then the box would be accelerating vertically.