Introduction:
When a meteorite enters the Earth's atmosphere, it undergoes a process called atmospheric entry. During this process, the meteorite experiences intense heating due to the friction between its surface and the air molecules. As a result, the meteorite starts to burn and eventually disintegrates before reaching the Earth's surface. This burning process significantly affects the linear momentum of the meteorite.

Conservation of Linear Momentum:
Linear momentum is a vector quantity that represents the motion of an object in a straight line. According to the law of conservation of linear momentum, the total linear momentum of a system remains constant if no external forces act on it. This means that the initial linear momentum of the meteorite before entering the atmosphere should be conserved during its journey.

Changes in Linear Momentum:
When a meteorite enters the Earth's atmosphere, several factors influence its linear momentum:

1. Initial Momentum: The meteorite possesses an initial linear momentum based on its mass and velocity before entering the atmosphere.

2. Atmospheric Drag: As the meteorite moves through the atmosphere, it experiences a drag force due to the air resistance. This force acts in the opposite direction to its motion, gradually decreasing its velocity.

3. Heat Transfer: The intense heating during atmospheric entry causes the meteorite's surface to burn, resulting in the loss of mass. The burning process releases gases and fragments, which are carried away by the surrounding air. This loss of mass affects the meteorite's linear momentum.

4. Disintegration: The burning and disintegration of the meteorite lead to the fragmentation of its mass. The smaller fragments may have different velocities and directions, altering the overall linear momentum of the system.

5. Final Linear Momentum: By the time the meteorite completely disintegrates, its linear momentum may have changed due to the factors mentioned above. The final linear momentum of the system will depend on the remaining mass, velocity, and direction of the fragments.

Conclusion:
When a meteorite burns in the atmosphere before reaching the Earth's surface, its linear momentum undergoes changes due to atmospheric drag, heat transfer, and disintegration. The initial momentum of the meteorite is gradually reduced by the drag force and altered by the loss of mass during burning. The disintegration of the meteorite further affects its linear momentum as smaller fragments may have different velocities and directions. Therefore, the linear momentum of a meteorite is not conserved throughout its journey through the Earth's atmosphere.