Difference Between Speed and Acceleration
Speed and acceleration are two terms associated with the motion of a body and you can find them being used in physics in the correct sense. Speed is defined as the distance covered by a body in a particular unit of time irrespective of its direction. This is just one dimensional unit and hence a scalar quantity. When we talk about velocity, which is a similar term then we take the direction of the motion into consideration and that is why velocity is a vector quantity. This means that we can say that speed is the magnitude of velocity in a particular direction.
You can simply calculate speed by diving the total distance covered by the time taken to cover that distance. Acceleration is the word that we commonly use and hear in context to driving. It is the rate at which the speed is changed. Acceleration also considers direction so we can say that it is the rate of change of velocity instead of speed.
When we drive a car and increase the speed, we say that we are accelerating. This means that we are changing the speed. If you do not change the speed and drive at a constant speed without changing the direction then there will be zero acceleration but if speed remains same but direction is changed then there will be acceleration because we consider the direction in case of acceleration. Hence it is also a vector quantity.
The SI nit of speed is m/sec and that of acceleration is m/sec2. You must have heard a word called deceleration. It is the opposite of acceleration and it means that the object has gradually slowed down or come to rest.