Choose one or more correct alternatives.

Which of the forces involved in dragging a heavy object on a smooth, horizontal surface, have the same magnitude?

i. the horizontal applied force

ii. gravitational force

iii. reaction force in vertical direction

iv. force of friction

Option(ii) gravitational force, Option(iii) reaction force in vertical direction

Explanation:

When an object is dragged on any surface it experiences four forces, the Horizontal applied force, frictional force in direction opposite to the applied force, Gravitational force in vertically downward direction due to earth’s gravity and Reaction force due to surface in vertically upward direction.

All the forces have been shown in figure

Gravitational force and reaction due to Surface are cancelling each other as there is no displacement in vertical direction, i.e. forces are balanced in vertical direction, so their magnitude should be same and direction should be opposite as is the case. Frictional force should be less than applied force for the box to move or start motion.