If only an external force can change the momentum of the

Solution 18Q:

We have to explain the reason behind how do the internal force by the engine of the car accelerate it without the help of an external force.

Step 1 of 2

Concept:

        Newton's first law: A body continues in its state of rest or of uniform motion unless and until it is acted upon by an external force.

        Law of Conservation of linear momentum: In the absence of external forces acting on the system, the final momentum of the system is equal to the initial momentum of the system.

        Law of conservation of energy: The total amount of energy in an isolated system remains constant. It can only be converted from one form to other.