# Which Refers To The Rate Of Change In Velocity

In physics acceleration is the rate of change of velocity of an object with respect to time. An object’s acceleration is the net result of any and all forces acting on the object as described by Newton’s Second Law. The SI unit for acceleration is meter per second squared (m/s2).

Accelerations are vector quantities (because they have both magnitude and direction). As a vector the calculated acceleration is the magnitude of the vector sum of the individual accelerations.

There are three commonly used methods to calculate acceleration:

1) Change in velocity (Δv) divided by change in time (Δt):

a = Δv/Δt

2) Final velocity (vf) minus initial velocity (vi) divided by change in time (Δt):

a = (vf – vi)/Δt

3) Instantaneous acceleration at any given time can be found by taking the derivative of velocity (v) with respect to time (t):

a = dv/dt

The acceleration of an object is directly proportional to the magnitude of the force acting on the object and inversely proportional to the mass of the object. The relationship between acceleration force and mass is described by Newton’s Second Law:

F = ma

where F is the force acting on the object m is the mass of the object and a is the acceleration of the object.

There are two types of acceleration: linear acceleration and angular acceleration. Linear acceleration is the acceleration of an object in a straight line and is described by the above equations. Angular acceleration is the acceleration of an object around a point or axis and is described by the following equation:

α = Δω/Δt