A person is standing on a frictionless horizontal ground. How can he move by a certain distance on this ground?

On a frictionless horizontal ground, a person cannot move by walking, running, or jumping because these actions require static friction to provide a horizontal reaction force. Friction is the force that opposes relative motion and allows a person to push against the ground to move forward [1]. In the absence of friction, internal forces cannot change the motion of the center of mass of a system unless mass is expelled. Sneezing involves the rapid expulsion of air (mass) from the body. According to Newton's Third Law and the conservation of linear momentum, the momentum of the expelled air must be balanced by an equal and opposite momentum imparted to the person's body. This 'recoil' effect, similar to rocket propulsion, provides the necessary external force to move the person a certain distance on a frictionless surface.

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 5: Exploring Forces > Activity 5.3: Let us investigate > p. 68