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There are two main descriptions of motion: dynamics and kinematics.Dynamics is general, since the momenta, forces and energy of the particles are taken into account. In this instance, sometimes the term dynamics refers to the differential equations that the system satisfies (e.g., Newton's second law or Euler–Lagrange equations), and sometimes to the solutions to those equations.
Snap, [6] or jounce, [2] is the fourth derivative of the position vector with respect to time, or the rate of change of the jerk with respect to time. [4] Equivalently, it is the second derivative of acceleration or the third derivative of velocity, and is defined by any of the following equivalent expressions: = ȷ = = =.
Multiplying by the operator [S], the formula for the velocity v P takes the form: = [] + ˙ = / +, where the vector ω is the angular velocity vector obtained from the components of the matrix [Ω]; the vector / =, is the position of P relative to the origin O of the moving frame M; and = ˙, is the velocity of the origin O.
The general case of a rotating rigid body can be modeled using kinematic screw theory, which includes one axial vector, angular velocity Ω(t), and one polar vector, linear velocity v(t). From this, the angular acceleration is defined as
From the foregoing, you can see that the time domain equations are simply scaled forms of the angle domain equations: is unscaled, ′ is scaled by ω, and ″ is scaled by ω². To convert the angle domain equations to time domain, first replace A with ωt , and then scale for angular velocity as follows: multiply x ′ {\displaystyle x'} by ...
For convenience, consider contact with the spring occurs at t = 0, then the integral of the product of the distance x and the x-velocity, xv x dt, over time t is 1 / 2 x 2. The work is the product of the distance times the spring force, which is also dependent on distance; hence the x 2 result.
This equation states that the kinetic energy (E k) is equal to the integral of the dot product of the momentum (p) of a body and the infinitesimal change of the velocity (v) of the body. It is assumed that the body starts with no kinetic energy when it is at rest (motionless).
Unprimed quantities refer to position, velocity and acceleration in one frame F; primed quantities refer to position, velocity and acceleration in another frame F' moving at translational velocity V or angular velocity Ω relative to F. Conversely F moves at velocity (—V or —Ω) relative to F'. The situation is similar for relative ...