# ⓘ Acceleration ..

## Instantaneous acceleration

In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities. The orientation of an objects acceleration is given by the orientation of the net force acting on that object. The magnitude of an objects acceleration, as described by Newtons Second Law, is the combined effect of two causes: the net balance of all external forces acting onto that object - magnitude is directly proportional to this net resulting force; that objects mass, depending on the materials out of which it is made - magnitude is inversely proporti ...

## Acceleration (special relativity)

Accelerations in special relativity follow, as in Newtonian Mechanics, by differentiation of velocity with respect to time. Because of the Lorentz transformation and time dilation, the concepts of time and distance become more complex, which also leads to more complex definitions of "acceleration". SR as the theory of flat Minkowski spacetime remains valid in the presence of accelerations, because general relativity is only required when there is curvature of spacetime caused by the energy-momentum tensor. However, since the amount of spacetime curvature is not particularly high on Earth o ...

## Accelerometer

An accelerometer is a device that measures proper acceleration. Proper acceleration, being the acceleration of a body in its own instantaneous rest frame, is not the same as coordinate acceleration, being the acceleration in a fixed coordinate system. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earths gravity, straight upwards of g ≈ 9.81 m/s 2. By contrast, accelerometers in free fall will measure zero. Accelerometers have multiple applications in industry and science. Highly sensitive accelerometers are components of inertial navi ...

## Angular acceleration

Angular acceleration is the time rate of change of angular velocity. In three dimensions, it is a pseudovector. In SI units, it is measured in radians per second squared, and is usually denoted by the Greek letter alpha. Just like angular velocity, there are two types of angular acceleration: spin angular acceleration and orbital angular acceleration, representing the time rate of change of spin angular velocity and orbital angular velocity respectively. Unlike linear acceleration, angular acceleration need not be caused by a net external torque. For example, a figure skater can speed up h ...

## Centrifugal force

In Newtonian mechanics, the centrifugal force is an inertial force that appears to act on all objects when viewed in a rotating frame of reference. It is directed away from an axis passing through the coordinate systems origin and parallel to the axis of rotation. If the axis of rotation passes through the coordinate systems origin, the centrifugal force is directed radially outwards from that axis. The concept of centrifugal force can be applied in rotating devices, such as centrifuges, centrifugal pumps, centrifugal governors, and centrifugal clutches, and in centrifugal railways, planet ...

## Centripetal force

A centripetal force is a force that makes a body follow a curved path. Its direction is always orthogonal to the motion of the body and towards the fixed point of the instantaneous center of curvature of the path. Isaac Newton described it as "a force by which bodies are drawn or impelled, or in any way tend, towards a point as to a centre". In Newtonian mechanics, gravity provides the centripetal force responsible for astronomical orbits. One common example involving centripetal force is the case in which a body moves with uniform speed along a circular path. The centripetal force is dire ...

## ⓘ Acceleration

• In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities they have magnitude
• Angular acceleration is the time rate of change of angular velocity. In three dimensions, it is a pseudovector. In SI units, it is measured in radians
• In physics, gravitational acceleration is the free fall acceleration of an object in vacuum - without any drag. This is the steady gain in speed caused
• In computing, hardware acceleration is the use of computer hardware specially made to perform some functions more efficiently than is possible in software
• proper acceleration is the physical acceleration i.e., measurable acceleration as by an accelerometer experienced by an object. It is thus acceleration relative
• Acceleration due to gravity may refer to Gravitational acceleration the acceleration caused by the gravitational attraction of massive bodies in general
• of relativity, four - acceleration is a four - vector vector in four - dimensional spacetime that is analogous to classical acceleration a three - dimensional
• Sudden unintended acceleration SUA is the unintended, unexpected, uncontrolled acceleration of a vehicle, often accompanied by an apparent loss of braking
• Plasma acceleration is a technique for accelerating charged particles, such as electrons, positrons, and ions, using the electric field associated with