Frame of reference

Definition

A frame of reference is a coordinate system or set of axes within which to measure the position, orientation, and other properties of objects in it. It is essential for describing motion accurately.

5 Must Know Facts For Your Next Test

1. A frame of reference can be inertial (non-accelerating) or non-inertial (accelerating).
2. In an inertial frame of reference, Newton's first law holds true: an object remains at rest or in uniform motion unless acted upon by a force.
3. The choice of a frame of reference can simplify the analysis of motion; for example, choosing a frame where one object is at rest.
4. Relative velocity between two objects depends on the frames of reference from which each object's velocity is measured.
5. Transformations between different frames of reference are often necessary to solve problems involving relative motion.

Review Questions

• What distinguishes an inertial frame of reference from a non-inertial one?
• How does changing the frame of reference affect the observed velocity of an object?
• Why is it important to specify a frame of reference when describing motion?

Related terms

Inertial Frame: A frame of reference in which objects obey Newton's first law, remaining at rest or moving uniformly unless acted upon by forces.

Non-Inertial Frame: A frame of reference that is accelerating, causing apparent forces like centrifugal force to appear.

Relative Velocity:

$v_{AB} = v_A - v_B$, where $v_A$ and $v_B$ are velocities measured in the same frame. It describes how fast one object is moving compared to another.