The acceleration concept, has nothing to do with going moving fast. It is a concept that has often been misused in real life, however, its meaning is very different physics. It is very common to hear that this concept is used to indicate that an object is moving at high speed which is incorrect. The term refers to the change acceleration in the speed of an object. Whenever an object changes its speed, in terms of its magnitude and direction, we say that is accelerating.
Acceleration, also known as linear acceleration is the change of speed of an object per unit time. The speed is defined as a vector, ie, has module (magnitude) and direction and sense. You can deduce when an object accelerates, it changes its speed (the magnitude of velocity), its direction of motion, or both. If an object is released and allowed to fall freely, it accelerated down. If an object is attached to a string and is rotated in a circle above the head with a constant speed, the object also experience a uniform acceleration in this case, the acceleration is the same direction as the rope and is directed towards the person's hand.
Acceleration is the rate of change in velocity over time. That is, the acceleration refers to how fast a moving object changes its speed. For example, an object resting portion and reaches a speed of 20 km / h, has accelerated. However, if an object takes four seconds to reach the speed of 20 km / h, will have greater acceleration than another object it will take six seconds to reach that speed.