Dynamics (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]
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 extertion or pressure which can cause an object to move. In Wikipedia, the concept of force is used to describe an influence which causes a free body to undergo an acceleration. It can be a push or a pull, which causes an object to change direction, speed or velocity, or to deform temporarily or permanently. Generally speaking, force causes an object's state of motion to change.[2]
In addition, when studying dynamics, vectors are used to describe forces.
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.
Summary
- Forces cause acceleration and have the ability to cause acceleration.
- If an object is accelerating, the net force is not zero.
- To find the net force, take the vector sum of all component forces
- To find the acceleration, use the equation Fnet=ma.
- If forces act at angles, trigonometry is needed to solve: [Fx=Fcos(0)] [Fy=Fsin(0)]
- If forces act along the axes, no trigonometry is needed to solve.
See also
References
