Table of Contents

## What is Acceleration?

**Acceleration**, refers to the rate at which an object’s velocity changes over time. It can be thought of as how quickly something speeds up. When an object accelerates, its speed or direction, or both, change. For instance, when a car speeds up, slows down, or turns, it is experiencing acceleration.

## Formula of Acceleration

The **acceleration formula** relates the change in velocity of an object to the time it takes for that change to occur. The acceleration formula is used to calculate the change in velocity of an object over a period of time. It is given by:

where:

**Acceleration (a):**is the rate of change of velocity. It is measured in meters per second squared (m/s²).**Final velocity (v):**is the velocity of the object at the end of the time period. It is measured in meters per second (m/s).**Initial velocity (u):**is the velocity of the object at the beginning of the time period. It is also measured in meters per second (m/s).**Time taken (t):**is the duration of the time period during which the velocity changes. It is measured in seconds (s).

## What is the Unit of Acceleration?

The unit of acceleration can be determined by dividing the unit of velocity by the unit of time.

Velocity is typically measured in meters per second (m/s), and time is measured in seconds (s). When we divide velocity (m/s) by time (s), we get meters per second per second, which is expressed as meters per second squared (m/s²).

So, the unit of acceleration is meters per second squared (m/s²).

### What is the Positive and Negative Acceleration?

**Positive acceleration:**When an object experiences positive acceleration, it means that its velocity is increasing over time. In other words, the object is speeding up or moving in the direction of its velocity.**Negative acceleration (deceleration):**Negative acceleration, often referred to as deceleration occurs when an object’s velocity decreases over time. The object is slowing down or moving in the opposite direction of its velocity.

In simpler terms, positive acceleration implies that an object is moving faster, while negative acceleration (deceleration) implies that it is slowing down.

### Solved Examples on Acceleration Formula:

**Example 1: **A car accelerates from rest to a velocity of 30 m/s in 5 seconds. What is its acceleration?

**Solution:**

Given:

Initial velocity (u) = 0 m/s

Final velocity (v) = 30 m/s

Time (t) = 5 s

Using the equation v = u + at, we can solve for acceleration (a):

30 = 0 + a x 5

30 = 5a

Dividing both sides by 5, we get:

a = 30 / 5

a = 6 m/s²

Therefore, the acceleration of the car is 6 m/s².

**Example 2: **A ball is dropped from a height of 40 meters. It takes 2 seconds to reach the ground. What is its acceleration?

**Solution: **

Given:

Initial velocity (u) = 0 m/s (the ball is dropped, so its initial velocity is zero)

Time (t) = 2 s

Displacement (s) = -40 m (negative sign indicates motion in the downward direction)

Using the equation s = ut + (1/2)at², we can solve for acceleration (a):

-40 = 0 + (1/2) x a x 22

-40= a x 2

Dividing both sides by 2, we get:

a = -40 / 2

a = -20 m/s²

Therefore, the acceleration of the ball is -20 m/s² (negative sign indicates acceleration in the downward direction).

## Acceleration Formula in Different Context

### Acceleration Formula with Force and Mass

Newton’s second law explains that force is equal to mass multiplied by acceleration (F = ma). To find the mass, you can rearrange the equation to mass equals force divided by acceleration (m = F/a). Similarly, to find acceleration, you rearrange it to acceleration equals force divided by mass (a = F/m).

### Acceleration Formula with Distance and Time

To calculate acceleration using distance and time, you can use the following formula:

If only distance (s) and time (t) are known, and starting from rest (u = 0):

**𝑎 = 2𝑠/𝑡 ^{2}**

where:

- 𝑎 is acceleration
- 𝑠 is distance
- 𝑡 is time

### Acceleration Formula with Mass

Acceleration formula with mass states that the acceleration (a) of an object is equal to the net force (F) acting on it divided by its mass (m). The formula is:

**𝑎 = F/ m**

## FAQs on Acceleration Formula

### What is acceleration formula by time?

The acceleration formula involving time is a = v-u/t Here, v is final velocity, u is initial velocity, and t is time. This formula helps in calculating how quickly an object speeds up or slows down over time.

### What is the SI unit of acceleration?

The SI unit of acceleration is meters per second squared (m/s²). This unit measures how quickly an object's speed changes in a specific direction over time.

### What is acceleration formula 9th class?

For 9th class, the acceleration formula is 𝑎 = 𝑣−𝑢/𝑡. Here, 𝑎 stands for acceleration, 𝑣 is final velocity, 𝑢 is initial velocity, and 𝑡 is the time taken. This formula is part of basic physics to understand motion.

### What is acceleration?

Acceleration is the rate at which an object's velocity changes over time. It measures how quickly the speed or direction of an object changes.

### How is acceleration defined?

Acceleration is defined as the change in velocity divided by the time taken for that change. It is represented by the formula: acceleration (a) = (final velocity - initial velocity) / time.

### What causes acceleration?

Acceleration is caused by forces acting on an object. Newton's second law of motion states that the acceleration of an object is directly proportional to the net force applied to it and inversely proportional to its mass.

### What is the difference between speed and acceleration?

Speed is a scalar quantity that represents how fast an object is moving, while acceleration is a vector quantity that represents how quickly an object's velocity is changing. Acceleration includes changes in both speed and direction.

### What is negative acceleration?

Negative acceleration, also known as deceleration, refers to a decrease in velocity over time. It indicates that an object is slowing down. Negative acceleration is represented by a negative value in calculations.

### What is uniform acceleration?

Uniform acceleration occurs when an object's velocity changes by the same amount in equal time intervals. In such cases, the object's acceleration remains constant.

### Can an object have acceleration without changing its speed?

Yes, an object can have acceleration without changing its speed if there is a change in its direction. Acceleration is not solely dependent on changes in speed but also on changes in direction.