Understanding Frame of Reference | Physics for EmSAT Achieve PDF Download

What is Frame of Reference?

A frame of reference comprises coordinate axes that establish the location of a particle in either two or three dimensions. The fundamental frame of reference, known as the Cartesian coordinate system, uses three coordinates (x, y, and z) to determine the position of a particle.

Types of Frames of Reference

Following are the two types of frame of reference

• Inertial Frame of Reference
  • When no force is acting and the body is in constant motion, the frame of reference is inertial. When the bodies in this frame follow Newton’s law of inertia and other Newtonian mechanics laws. Unless acted upon by an external force, a body in this frame remains at rest or in continuous motion.
  • Example of Inertial Frame of Reference
    • A truck, for example, moving at a constant speed provides an inertial frame of reference for the people inside. A motionless ramp down which objects can roll is another example. An inertial frame of reference is one in which there is no acceleration.
• Non-Inertial Frame of Reference
  • A non-inertial frame is defined as an accelerated frame for an inertial frame of reference. Newton’s laws cannot be applied in a non-inertial frame of reference.
  • When a body is accelerated without being acted on by an external force, the frame of reference is said to be non-inertial.
• Example of Non-Inertial Frame of Reference
  • A train moving at a constant speed and a car turning at a constant speed are both examples of inertial and non-inertial reference frames. Non-inertial reference frames are those that accelerate either linearly or rotate around an axis.

Frame of Reference Examples

Some real-life examples of frames of reference are given below:

• Earth's Surface: For most everyday situations, we use the Earth's surface as our frame of reference. When you say you are standing still, you mean you are not changing your position relative to the ground.
• Aircraft in Flight: Pilots and passengers inside an airplane use the aircraft itself as a frame of reference. The sensation of turbulence or banking during a turn is perceived relative to the motion of the plane.
• Watching a Sports Game: When watching a soccer match, the stands or the TV screen serve as your frame of reference. You observe the players' motion relative to the field or screen.
• Elevator Ride: In an elevator, the frame of reference can change. When the elevator accelerates upward, you feel heavier, and when it descends, you feel lighter. These sensations are due to your motion relative to the elevator.
• Space Travel: Astronauts in a spacecraft use the spacecraft as their frame of reference. Their perception of motion and gravity is relative to the spacecraft's movement.

Difference between Inertial and Non-Inertial Frame of Reference

Some main differences between inertial and non-inertial frame of reference are as follows.