Is acceleration scalar or vector quantity?
In this article let us learn about definition of mechanics, scalar and vector quantities, velocity and acceleration
Mechanics: Mechanics is a branch of physics that deals with bodies at rest or in motion, under the action of some forces. The two branches of mechanics are: Dynamics and statics
Dynamics is that branch of mechanics which deals with the action of forces on bodies in motion.
Statics is the branch of mechanics which deals with the action of forces on bodies, the forces being so arranged that the bodies are at rest.Check if Acceleration Scalar or Vector Quantity?
Motion: A particle is said to be in motion when it changes its position relative to any object and occupies different position at different times.
Scalar Quantities: These are quantities that have only magnitude but have no  direction
Ex: time, mass, volume
Vector quantities: These are quantities that have both magnitude and direction. Examples: force, velocity etc…
Displacement: The displacement of a moving point or body is its change of position. So displacement has both magnitude and direction. Displacement is a vector quantity.
SI unit of displacement is meter (m).
Velocity: The velocity of a moving body is the rate of displacement. From the definition, velocity has both magnitude and direction. Hence, velocity is a vector quantity.  SI unit is m/s.
Acceleration: The acceleration of a moving point is the rate of change of its velocity. Since velocity is a vector quantity obviously acceleration is also a vector quantity.
SI unit is m/s^2
Acceleration, a = Change in velocity /time = `(v - u)/(t)` where v is the final velocity and u is the initial velocity.
Uniform acceleration: The acceleration is uniform when equal changes of velocity take place in equal intervals of time however small the intervals may be.

Retardation or deceleration:
Implies decrease in the magnitude of velocity. It is also called as negative acceleration.Conclusion on Discussion whether Acceleration is a Vector or a Scalar
As acceleration is defined as the rate of change of velocity, acceleration is also a vector quantity, which has both magnitude and direction.