instantaneous acceleration

of: a particle (relative to a specific frame of reference)

at: a given time

is: a vector quantity that specifies the rate of change of the particle's velocity at time [M4.1, P2.1, P2.2]

is represented: by the vector That is, [M4.1, P2.1, P2.2]

has as its SI unit: [M4.1]

can be determined: as the limiting value of average acceleration, calculated over shorter and shorter time intervals. [M4.1, P2.1, P2.2]

also can be determined: as the gradient of a velocity-time graph at time [M4.1, P2.1, P2.2]

usually is known: simply as acceleration. [M4.1, P2.1, P2.2]