*What is Acceleration* *?*

Acceleration is the rate at which an object changes its velocity over time. In other words, it is the measure of how quickly the speed of an object changes. **It is a vector quantity**, which means it has both magnitude and direction.

Acceleration can occur in several different ways, including increasing speed, decreasing speed, or changing direction. It is calculated as the change in velocity divided by the time taken for the change to occur.** The SI unit of acceleration is meters per second squared (m/s^2).**

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__example__,- If a car is traveling at a constant speed of 50 km/h and then suddenly accelerates to a speed of 100 km/h in 10 seconds, its acceleration would be 5 m/s^2. This means that every second, the car's velocity increases by 5 meters per second.

*Constant acceleration*

** Definition : **Constant acceleration is the type of acceleration that occurs when an object's velocity changes at a constant rate over time. In other words, it is the rate at which the object's speed or direction changes that remains the same throughout the duration of the motion.

**A common example of constant acceleration** is a free-falling object, such as a ball dropped from a certain height. In this case, the object's acceleration is constant and equal to the acceleration due to gravity, which is approximately 9.81 meters per second squared (m/s^2) near the Earth's surface. This means that the object's velocity will increase by 9.81 m/s every second it falls.

*Example:*

A car moving in a straight line, where the driver accelerates or decelerates the car at a constant rate. In this case, the car's acceleration is constant as long as the driver maintains a steady rate of acceleration or deceleration.

Constant acceleration can be described mathematically using the formula:

**a = (v_f - v_i) / t**

**where ,**

"**a"** is the acceleration,

**"v_f"** is the final velocity,

**"v_i" **is the initial velocity, and

**"t"** is the time interval.

*Acceleration Vector Direction*

**The direction of the acceleration vector is determined by the direction of the net force acting on an object.**The acceleration vector always points in the same direction as the net force.

**Newton's Second Law of Motion**, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. In other words, the greater the net force, the greater the acceleration, and the smaller the mass, the greater the acceleration.

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