Why can't the magnet car work?

(Dan Tri) - The initial idea sounds quite interesting, but why can't it be implemented?

Imagine a car with a large magnet attached to the front, and another magnet suspended in front of the car to create attraction.

Hypothetically, the magnetic force would pull the car forward, without fuel or electricity, moving forever. But if that were possible, humanity would have solved the global energy crisis long ago.

The idea of using magnets to create practical motion has been seriously studied by humans for centuries. As early as 1269, the scientist Petrus Peregrinus de Maricourt outlined the principle of a wheel rotating by magnetic attraction.

In the 17th century, John Wilkins proposed a model that used gravity to push an iron ball to create an endless loop.

Despite their elaborate and eye-catching designs, all of these models failed to maintain motion, simply because they violated Newton's laws of motion, the core foundation of classical physics.

Specifically, the First Law of Motion states that an object at rest will continue to remain at rest unless acted upon by an external force.

The key is external force (Illustration).

In the magnet truck model, both the truck and the magnet are in a closed system, and the attraction between them only works within that system. Therefore, there will be no external repulsive force acting on the truck to make it move.

One analogy many physicists use is that of a rubber band. Imagine you tie a large rubber band to the front of your car, then reach out the window and pull the band forward.

No matter how hard you pull, the car will not move, because all the force you create is within the system of you and the car. There is no external force created to change the initial stationary state.

Newton's third law of motion also helps explain this. When one object exerts a force on another object, that object will exert an equal and opposite force on the first object.

In the case of a magnetized vehicle, the attraction between the two magnets does not produce an overall motion, because the action and reaction forces cancel each other out within the system. As a result, the vehicle remains stationary, despite all seemingly “creative” efforts.

Some people humorously suggest that if a magnetic car can pull itself forward, then we have accidentally invented a form of perpetual motion, which the laws of dynamics have proven impossible.

A machine that can maintain its own motion without consuming energy has been a dream for centuries, but unfortunately, it has remained just that... dream.

Source: https://dantri.com.vn/khoa-hoc/vi-sao-xe-gan-nam-cham-khong-the-hoat-dong-20250803065252211.htm