Dynamics (mechanics)
 | It has been suggested that Analytical dynamics be merged into this article. (Discuss) Proposed since May 2010. |
| Part of a series on |
| Classical mechanics |
|---|
In the field of physics, the study of the causes of motion and changes in motion is dynamics. In other words the study of forces and why objects are in motion. Dynamics includes the study of the effect of torques on motion. These are in contrast to kinematics, the branch of classical mechanics that describes the motion of objects without consideration of the causes leading to the motion.
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, Isaac Newton established the undergirding 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 consideration, because these are interrelated in any given observation or experiment.[1]
The study of dynamics falls under two categories: linear and rotational. Linear dynamics pertains to objects moving in a line and involves such quantities as force, mass/inertia, displacement (in units of distance), velocity (distance per unit time), acceleration (distance per unit of time squared) and momentum (mass times unit of velocity). Rotational dynamics pertains to objects that are rotating or moving in a curved path and involves such quantities as torque, moment of inertia/rotational inertia, angular displacement (in radians or less often, degrees), angular velocity (radians per unit time), angular acceleration (radians per unit of time squared) and angular momentum (moment of interia times unit of angular velocity). Very often, objects exhibit linear and rotational motion.
For classical electromagnetism, it is Maxwell's equations that describe the dynamics. And the dynamics of classical systems involving both mechanics and electromagnetism are described by the combination of Newton's laws, Maxwell's equations, and the Lorentz force.
Force
From Newton, force can be defined as an exertion or pressure which can cause an object to move. The concept of force is used to describe an influence which causes a free body (object) to accelerate. It can be a push or a pull, which causes an object to change direction, have new velocity, or to deform temporarily or permanently. Generally speaking, force causes an object's state of motion to change.[2]
Newton's laws
Newton described force as the ability to cause a mass to accelerate.
- Newton's first law states that an object in motion will stay in motion unless a force is applied. This law deals with inertia, which is a property of matter that resists acceleration and depends only on mass.
- Newton's second law states that force quantity is equal to mass multiplied by the acceleration (F = ma).
- Newton's third law states that for every action, there is an equal but opposite reaction.
See also
References
- ^ Goc, Roman (2004-2005 copyright date). "Dynamics" (Physics tutorial). Retrieved 2010-02-18.
{{cite web}}: Check date values in:|date=(help) - ^
Goc, Roman (2004-2005 copyright date). "Force in Physics" (Physics tutorial). Retrieved 2010-02-18.
{{cite web}}: Check date values in:|date=(help)
Further reading
- Swagatam (25 March 011). "Calculating Engineering Dynamics Using Newton's Laws". Bright Hub. Retrieved 2010-04-10.
{{cite web}}: Check date values in:|year=(help) - Wilson, C. E. (2003). Kinematics and dynamics of machinery. Pearson Education. ISBN 978-0-201-35099-9.
- Dresig, H.; Holzweißig, F. (2010). Dynamics of Machinery. Theory and Applications. Springer Science+Business Media, Dordrecht, London, New York. ISBN 978-3-540-89939-6.
{{cite book}}: CS1 maint: multiple names: authors list (link)