Frames of Reference

A frame of reference is made up of an abstract coordinate system and a set of physical reference points that are used to fix the coordinate system and standardise measurements within the frame of reference. It is necessary to have a reference point in order to determine the change in position of an object. A coordinate system that is associated with a time frame is referred to as a frame of reference.

Reference Frame

An arbitrary system of graduated lines symbolically attached to a body that is used to describe the position of points in relation to that body is known as a frame of reference. To describe the location of a point on the surface of the Earth, degrees of latitude can be used, measured north and south from the Equator, and degrees of longitude, measured east and west from the great circle passing through Greenwich, England, and the poles can be used.

Axes (lines) radiating from a point known as the origin serve as reference frames in dynamics. Coordinate systems are used to represent these reference frames. When a point moves parallel to a plane (plane motion), the position of the point can be described by two numbers: a. either the distances between a point and two lines at right angles to one another on the plane (rectangular coordinates), or b. either the length of a line with one end fixed at the origin and one end at the moving point, as well as the angle that the line makes with a fixed axis (polar coordinates). When it comes to three-dimensional motion, three rectangular coordinates are used, or the length of a line emanating from the origin and two angles (spherical coordinates) are used; one of these angles is equivalent to degrees of longitude and the other is equivalent to degrees of latitude. When a line connecting the origin and a point is drawn, the line is referred to as the position vector for the point in question. When a point moves, the position vector changes in both magnitude and direction, and the velocity of the point is defined in terms of the magnitude and direction of these changes.

Newton’s laws of motion are valid only in a coordinate system that is at rest with respect to the “fixed” stars, according to the strictest interpretation. A Newtonian reference frame, also known as an inertial reference frame, is a system that operates in this manner. Moreover, the laws hold true in any set of rigid axes that moves with constant velocity and without rotation relative to the inertial frame; this concept is known as the principle of Newtonian or Galilean relativity, depending on which school of thought you follow. When you attach a coordinate system to the Earth, you are not using an inertial reference frame, which means the Earth is rotating and accelerating with respect to the Sun. When using an inertial reference frame, it is possible to obtain accurate solutions to most engineering problems. However, there are some applications in which the rotation of the Earth cannot be ignored, such as when using a gyroscopic compass, which is one of these applications.

When describing the position of a point that moves relative to a body that moves relative to the Earth, it is usually convenient to use a reference frame that is attached to the moving body to make the description more accurate. A moving automobile engine, for example, is of greater interest in its motion relative to the block than it is when it is moving relative to the ground; on the other hand, it may be of greater interest in its motion relative to other moving parts of the engine than it is in its motion relative to the block.

There are several different types of frames of reference

Inertial Frame of Reference

The term “inertial frame of reference” refers to a frame in which Newton’s law is valid. Therefore, if no external force acts on a body, it will remain at rest or will continue to move in a consistent manner. If a body is kept on the surface of the earth, it will be at rest for a person on the earth, but it will be in motion for a person on the moon, so which is my inertial frame here?

To be more precise, the term “inertial frame of reference” is relative, meaning that we first assume a reference frame to be the inertial frame of reference. A more general definition of an inertial frame would be: An inertial frame is either at rest or moves with constant velocity in relation to the inertial reference frame that I am assuming.

Non-inertial Frame of Reference

We can now define a non-inertial frame as a frame that has been accelerated in comparison to the assumed inertial frame of reference. It is impossible for Newton’s law to hold true in these frames. For example, if I assume that the earth is an inertial reference frame, the moon becomes a non-inertial reference frame because it is moving at a faster rate with respect to the earth in the previous example. However, in order to make Newton’s law work in this situation, we must employ some mysterious forces, also known as pseudo forces.

Conclusion

A frame of reference (also known as a reference frame) is an abstract coordinate system whose origin, orientation, and scale are specified by a set of reference points, which are geometric points whose positions have been mathematically determined by the frame of reference.