Why is it more difficult to walk on sand than on a concrete pavement?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. Sand displaces, reducing pushback.
Walking relies on Newton's Third Law of Motion: as you push against the ground, the ground pushes back with an equal force. On a concrete pavement, the surface is rigid, providing a firm reaction force that propels you forward efficiently. However, sand displaces and deforms under your weight. Much of the energy you exert is wasted in moving the sand particles rather than pushing your body forward. This lack of a solid "pushback" or reaction force makes your muscles work harder, leading to quicker fatigue.