What is Acceleration

As you go on studying physics, you will realize that a large part of it is devoted to the study of 'Motion', the causative agents of motion and the anatomy of motion. All kinds of motion are the result of the energy changes caused by the presence of unbalanced forces in nature. In the study of motion, one essential concept, which needs to be grasped is 'acceleration' of an object, caused by a force.

Definition

The best way to understand any physics concept is to relate it as much as possible with actual experience. You may not know what is acceleration but you have already felt it. When the car you are sitting in speeds up, what you feel is acceleration caused by the change in speed of the car. In technical terms, acceleration is defined to be the rate of change of velocity with time. Velocity is of course the rate of change of displacement with time in a specific direction.

Acceleration is not just the change in the magnitude of velocity (speed), but also indicates a change in the direction of displacement of any object. Force causes a change in velocity and causes an object to accelerate. The unit of linear acceleration is meters / sec².

What is Acceleration Formula?

The physics formula for acceleration is the same which defines the force acting on an object, in Newtonian mechanics. Here is the acceleration formula, which can let you calculate the magnitude of acceleration:

Acceleration (a) = Force (F) / Mass (m)

What is Angular Acceleration?

The acceleration caused in a body may not always be linear. Objects that rotate around a center feel an acceleration which is known as angular acceleration. It is defined in physical terms as the rate of change of angular velocity of any object wit time. The formula for angular acceleration is as follows:

Angular Acceleration (α) = dω/dt = τ / I

where ω is angular velocity, τ is the torque (rotational force) acting on an object and I is its moment of inertia.

What is Centripetal Acceleration

When you tie an object on a string and rotate it in a circular fashion, it feels a centripetal force directed towards the center. Where there is a force, there is acceleration and thus the object feels a centripetal acceleration directed towards the center of circular motion. The formula for calculation of centripetal acceleration is as follows:

Centripetal Acceleration (a) = v² / r

where v is the linear velocity or tangential velocity of the rotating object and r is the linear distance of the object from the center of rotation.

What is Acceleration Due to Gravity?

Although gravity is now understood to be a manifestation of the curvature of space time caused by mass, it can still be approximately described by Newton's law of gravitation. The force of gravity exerted on an object makes it accelerate. It is known as the acceleration due to gravity. The Newton's law of gravitation gives us the relation between gravitational force and acceleration:

F = Mass (m) x Acceleration Due to Gravity (g)

Since Earth is not a perfect sphere, the mass exerted by it is not exactly same on all points of its surface. The value of acceleration due to gravity, provided by the acceleration equation, varies from the equator to the poles. It is greater at the poles and has the lowest value at the equator, as Earth is actually shaped like a flattened sphere or oblate spheroid. The average value of acceleration due to gravity on Earth is 9.80665 m/s².

As we saw earlier, Newton's laws of motion establish the connection between force and acceleration. Ergo, using the Newton's laws and associated derived physics formulas, one can calculate the force acting on an object, by measuring the acceleration it causes.