Newton's Law of Resistance

Newton's Law of Resistance is a fundamental principle in fluid mechanics that explains the resistance experienced by a body when it moves through a fluid. The law states that the drag force experienced by a body moving through a fluid is directly proportional to the velocity of the body squared and the density of the fluid, and inversely proportional to the cross-sectional area of the body.

Assumption of Newton's Law of Resistance

The Newton's law of resistance is based on the following assumptions:

1. Planes of the body are completely smooth
The resistance experienced by a body moving through a fluid is affected by the roughness of the surface of the body. However, this assumption assumes that the planes of the body are completely smooth and there are no irregularities or roughness on the surface.

2. Space around the body is completely filled with the fluid
This assumption assumes that the body is moving through a fluid medium that completely fills the space around the body. This means that there are no empty spaces or gaps in the fluid that the body moves through.

3. Fluid particles do not exert any influence on one another
This assumption assumes that the fluid is made up of particles that do not interact or exert any influence on one another. This means that the fluid is treated as a continuous and homogeneous medium.

Importance of these assumptions

All of these assumptions are important in deriving the formula for the drag force experienced by a body moving through a fluid. If any of these assumptions are not met, the formula derived using Newton's Law of Resistance may not be accurate in predicting the drag force experienced by the body.

Conclusion

Newton's Law of Resistance is a fundamental principle in fluid mechanics that explains the resistance experienced by a body when it moves through a fluid. The law is based on the assumptions that the planes of the body are completely smooth, the space around the body is completely filled with the fluid, and the fluid particles do not exert any influence on one another. These assumptions are important in deriving the formula for the drag force experienced by a body moving through a fluid.