State in words Newton's second law of motion assuming mass is not a constant. Write down the general equation of motion assuming mass is not a constant.

Question: State in words Newton's second law of motion assuming mass is not a constant. Write down the general equation of motion assuming mass is not a constant.

Answer:

The Second law of thermodynamic states that "the rate of change of momentum of a particle over time is directly proportional to the force applied and it is in same direction as the applied force".

Mathematically,

Here, 

 is the momentum of particle, and  is the applied force to the particle.

Thus, 

Here, 

 is the mass of the particle and  is the velocity of the particle.

Here, 

 is the acceleration of the particle and  is the rate of change of the mass.

Thus, the above equation represents the general equation of the motion. From this equation, it can be said that the applied force accelerates the particle and also changes the mass with respect to time.