Difference Between Acceleration and Gravitational Field

Acceleration vs Gravitational Field

Acceleration and gravitational field are two concepts discussed under mechanics in physics. These two concepts are equally important when it comes to the understanding of the mechanics of nature. It is vital to have a good understanding about acceleration and gravitational field in the fields of astronomy, physics, engineering and rocket science. To some people these two concepts would look somewhat similar, to others these two would look totally out of place. In this article, we are going to get a good understanding about what are gravitational field and acceleration, their definitions, similarities and finally their differences.

Acceleration

Acceleration is defined as the rate of change of velocity of a body. It is important to notice that acceleration always requires net force acting on the object. This is described in Newton’s second law of motion. The second law states that the net force F on a body is equal to the rate of change of linear momentum of the body. Since the linear momentum is given by the product of mass and velocity of the body, and the mass does not change on a non-relativistic scale, the force is equal to mass times the rate of change of velocity, which is the acceleration. There can be several causes to this force. Electromagnetic force, gravitational force and mechanical force are to name a few. The acceleration due to a mass nearby is known as the gravitational acceleration. It must be noticed that if an object is not subjected to a net force the object will not change the velocity of itself, whether it was moving or stationary. Note that the movement of the object does not require a force, but the acceleration always does require a force.

Gravitational field

Gravitational field is a concept and a method for calculating and explaining phenomena happening around any object with a mass. A gravitational field is defined around any mass. According to Newton’s universal law of gravitation, two masses M and m divided by a finite distance r exerts a force F = G M m / r² on each other. If we take the case of m=1, we get a new equation, where F = GM/r². The gravitational field intensity of a point located on a distance r from the mass is defined as the force per unit mass on the point r, this is commonly termed as g, where g= GM/r². Since we know F = ma, and F = GMm/r^2, we can see that a = GM/r². This means that the gravitational field intensity and the acceleration due to the gravitational force are the same. This acceleration is known as the gravitational acceleration.