We explain what acceleration is and the formulas used to calculate it. Also, its difference with speed and examples.
What is acceleration?
The acceleration of an object is a magnitude that indicates how the speed of the object changes in a unit of time. Since velocity is a vector quantity (that is, it has a direction), acceleration is also a vector quantity. It is usually represented by the sign to and its unit of measurement in International System is m/s2 (meters per second squared).
The origin of acceleration as a concept comes from the mechanics studies of Isaac Newton (founder of classical mechanics), in which it is ensured that an object will maintain its rectilinear and uniform motion (MRU) unless forces act on it that lead to an acceleration.
These forces can produce accelerations that cause objects to increase or decrease their speeds. It is important to keep in mind that when working with vectors, it is essential to define directions. If, for example, we define east as the positive direction of motion, then a positive acceleration always implies an increase in speed. However, a negative acceleration may indicate a decrease in speed in the east direction, or an increase in speed in the west direction.
If an object experiences changes in its acceleration in a certain period of time, then what is defined as “average acceleration” can be calculated, which is the average of the accelerations it undergoes in that time range.
See also: Kinematics
acceleration formula
Classical mechanics understands acceleration as a change in the speed of a body over time. Mathematically this is written as: a = dv/dt where to is acceleration, d.v. the difference in speed and dt the time at which acceleration occurs.
More precisely, d.v. and dt They are defined as follows:
- dv = vF –vYo where vF is the final speed and vYo, the initial speed of the mobile. This difference indicates the direction of the acceleration.
- dt = tF –tYo where tF It is the final time and tYo the initial time of the movement. Unless otherwise stated, the initial time is usually taken as 0 seconds.
On the other hand, there is a proportionality relationship between the force (F) that applies to an object of mass (m), and acceleration (to) that you acquire. The formula that describes this relationship is Newton's second law:
- F = ma from which it follows that a = F/m
Speed and acceleration
speed and acceleration are two different concepts. Velocity indicates the amount of distance that a body travels in a unit of time (that is why it has units of m/s, for example), while acceleration is the variation of said speed in a unit of time (and that is why it has units of m/s2For example).
Examples of acceleration
- A billiard ball accelerates when hit with the cue. Knowing the force provided by the cue and the mass of the ball, we can obtain its acceleration.
- If we know the speed of a train just before it starts to brake and the time it takes to reach zero speed, then we can calculate its deceleration (negative acceleration).
- An object is thrown from a balcony (then its initial speed is zero) and due to the force of gravity, it will fall with a speed that will increase until it is maximum on the floor. If we know this final speed and the time it takes to fall, we can obtain the acceleration (which will be that of gravity).
