## What is acceleration?

**Acceleration (a) **is the change of velocity for a given object in motion with respect to time. The official SI unit of is **m/s ^{2}**. Newton’s second law states that the rate of acceleration for an object in motion is equal to the sum of all forces that act upon that object. It is a vector quantity. This means that apart from the magnitude, it also has a direction. The average acceleration of an object is calculated using the change of velocity ( Δv ) and the period ( Δt ).

When the magnitude is above 0, we are talking about *acceleration*. However, when it is below zero, we are talking about *deceleration*. Deceleration is the loss of velocity for a moving object.

Velocity and speed, while similar, are not the same. **Speed **is simply the rate at which a given object is moving, with no regard to direction. **Velocity **ascertains the object’s direction as well as the speed. Speed is a **scalar quantity**, while velocity is a **vector quantity**.

## Linear motion

Linear motion is a motion along a straight line. In other words, the moving object doesn’t change its direction. There are two types of linear motion: *uniform *and *non-uniform*.

**Uniform linear motion **is one where, as well as the direction, the velocity is also constant (*a=0*). This will go on until an external force acts upon an object in uniform linear motion. If this does happen, the velocity and the direction of the object will change.

**Non-uniform linear motion** involves a change of velocity (a≠0) caused by an external force acting upon the object. The change of velocity can also be uniform and non-uniform.

If an object is moving along a straight line with uniform acceleration, we can calculate its velocity using the following formula:

v= v_{0}+a*t**t **represents the period of the object’s motion. **v _{0}** represents the initial velocity. If the object started moving from a

*standstill*the initial velocity will be

*0*. If it was already in motion, v

_{0}will be the velocity of the object before it started accelerating.

## Acceleration formulas

Something that can help you for calculating acceleration is the pyramid:

Essentially, whatever you want to calculate, just cover it, and what is left will give you the formula. So, if you want to calculate **acceleration**, you would cover **a**, and what is left is:

For the **time **(t) it would be:

And for the **change in velocity **( Δv ), it would be:

The change of velocity can also be calculated by subtracting the initial velocity from the final velocity:

\Delta v = v-v_0If you want to calculate acceleration using the distance traveled (**d**[m]), you can use the following formula:

Another way of calculating acceleration is through the formula for force (**F** [N]):

For more about force, check out our Force Calculator!

## How to calculate acceleration?

Before this, we mentioned all the formulas you would need to calculate acceleration. Now, let’s do a quick example to show you what it’s all about.

Let’s say we have been given an object, and its initial velocity is 5 m/s. After 20 seconds of uniform acceleration, it has reached its final velocity of 250 m/s. What was the object’s acceleration?

a = \frac {v-v_0}{t} \\ a = \frac {250 \frac {m}{s}-5 \frac {m}{s}}{20s} \\ a = \frac {245 \frac {m}{s}}{20s} \\ a = 12.25 \frac {m}{s^2}So, the object was accelerating at a rate of 12.25 m/s^{2}.

Of course, the simplest way to do this calculation is using our calculator.

## Acceleration units

As we said, the official SI unit for acceleration is

\frac {m}{s^2}which is pronounced **meters per second squared **or **meters per second per second**. Out of course, there are many others. In the imperial system, the standard unit for acceleration is:

which is pronounced **feet per second squared**.

## Gravitational acceleration

**Gravitational acceleration **is that of a falling object in a vacuum. It is completely uniform. This is because objects do not experience drag while in a vacuum. It is caused by the force of **gravitational attraction**, and it is the same for every object, regardless of its mass or composition. **Gravimetry **is the study of these rates.

The standard value is defined as exactly 9.80665 m/s^{2}. However, it is often shortened to 9.81 m/s^{2}. It varies slightly at different points on Earth’s surface.

## Other forms of acceleration

**Centripetal acceleration** occurs when an object traverses a circular path. This happens because the direction is always changing, so the velocity has to as well. The product of this is acceleration. The formula for calculating it is:

**Proper acceleration **is acceleration of an object relative to a free-fall condition. For example, during a rocket launch, the rocket is rapidly accelerating. The proper acceleration is what the occupants feel. We measure it with an accelerometer.

**Instantaneous acceleration **is the limit of the average acceleration over on infinitesimal (infinitely small) interval of time.

## FAQ

**What does acceleration mean?**

Acceleration is the change of velocity with respect to time.

**How to calculate acceleration?**

The standard formula for calculating acceleration is a = Δv/Δt.

**Can acceleration be negative?**

If the value for acceleration is less than zero, it is called deceleration.

**Is acceleration a vector?**

Acceleration is a scalar quantity.

**What is the difference between velocity and acceleration?**

Velocity is the rate of change of an objects position, and it is a vector quantity. Acceleration is the rate of change of velocity, and it is a scalar quantity.

**Why does my car shake when I accelerate?**

Typically, this is due to a problem with the engine mounts or the suspension system.

**Which equations can be used to solve for acceleration?**

Another equation for calculating acceleration is a = F/m. For more formulas, check out our calculator.

**What is acceleration measured in?**

Acceleration is measured in m/s^{2} (meters per second squared).

**How does mass affect acceleration**

A more massive body requires a greater force to accelerate it than a less massive body, according to Newton’s second law of motion.

**How to find acceleration due to gravity?**

Gravitational acceleration, on average, is equal to 9.80665 m/s^{2}, although it varies on certain points of the Earth’s surface.