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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.
The formula for the acceleration A P can now be obtained as: = ˙ + + (), or = / + / +, where α is the angular acceleration vector obtained from the derivative of the angular velocity vector; / =, is the relative position vector (the position of P relative to the origin O of the moving frame M); and = ¨ is the acceleration of the origin of ...
The SI unit for acceleration is metre per second squared (m⋅s −2, ). For example, when a vehicle starts from a standstill (zero velocity, in an inertial frame of reference) and travels in a straight line at increasing speeds, it is accelerating in the direction of travel. If the vehicle turns, an acceleration occurs toward the new direction ...
These equations can be used only when acceleration is constant. If acceleration is not constant then the general calculus equations above must be used, found by integrating the definitions of position, velocity and acceleration (see above).
In physics, Torricelli's equation, or Torricelli's formula, is an equation created by Evangelista Torricelli to find the final velocity of a moving object with constant acceleration along an axis (for example, the x axis) without having a known time interval. The equation itself is: [1] = + where
An equation for the acceleration can be derived by analyzing forces. Assuming a massless, inextensible string and an ideal massless pulley, the only forces to consider are: tension force (T), and the weight of the two masses (W 1 and W 2). To find an acceleration, consider the forces affecting each individual mass.
For a body moving in a circle of radius at a constant speed , its acceleration has a magnitude = and is directed toward the center of the circle. [ note 9 ] The force required to sustain this acceleration, called the centripetal force , is therefore also directed toward the center of the circle and has magnitude m v 2 / r {\displaystyle mv^{2}/r} .
In this case, the three-acceleration vector is perpendicular to the three-velocity vector, = and the square of proper acceleration, expressed as a scalar invariant, the same in all reference frames, = + (), becomes the expression for circular motion, =. or, taking the positive square root and using the three-acceleration, we arrive at the ...