# Dynamics (mechanics)

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For dynamics as the mathematical analysis of the motion of bodies as a result of impressed forces, see analytical dynamics.

Dynamics is a branch of physics (specifically classical mechanics) concerned with the study of forces and torques and their effect on motion, as opposed to kinematics, which studies the motion of objects without reference to its causes. Isaac Newton defined the fundamental physical laws which govern dynamics in physics, especially his second law of motion.

## Principles

Generally speaking, researchers involved in dynamics study how a physical system might develop or alter over time and study the causes of those changes. In addition, Newton established the fundamental physical laws which govern dynamics in physics. By studying his system of mechanics, dynamics can be understood. In particular, dynamics is mostly related to Newton's second law of motion. However, all three laws of motion are taken into account because these are interrelated in any given observation or experiment.[1]

## Newton's laws

Newton described force as the ability to cause a mass to accelerate. His three laws can be summarized as follows:

1. First law: If there is no net force on an object, then its velocity is constant. The object is either at rest (if its velocity is equal to zero), or it moves with constant speed in a single direction.[2][3]
2. Second law: The rate of change of linear momentum P of an object is equal to the net force Fnet, i.e., dP/dt = Fnet.
3. Third law: When a first body exerts a force F1 on a second body, the second body simultaneously exerts a force F2 = −F1 on the first body. This means that F1 and F2 are equal in magnitude and opposite in direction.

Newton's Laws of Motion are valid only in an inertial frame of reference

## References

1. ^ Goc, Roman (2004-2005 copyright date). "Force in Physics" (PHYSICS TUTORIAL). Retrieved 2010-02-18. Check date values in: |date= (help)
2. ^ Browne, Michael E. (July 1999). Schaum's outline of theory and problems of physics for engineering and science (SERIES: SCHAUM'S OUTLINE SERIES). McGraw-Hill Companies. p. 58. ISBN 978-0-07-008498-8.
3. ^ Holzner, Steven (December 2005). Physics for Dummies. Wiley, John & Sons, Incorporated. p. 64. ISBN 978-0-7645-5433-9.