relative motion

physics

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July 13, 2026

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Relative motion refers to how an object's movement is observed or described in relation to another object or system that is considered fixed. This concept is fundamental in physics and is a cornerstone of special relativity, a theory developed by Albert Einstein in 1905.12

Special relativity deals with objects moving at constant velocities relative to each other, forming inertial frames of reference. It reveals that the speed of light is a universal limit and that mass and energy are interchangeable, as expressed by the famous equation (E = mc^2). The understanding of relative motion is crucial for comprehending phenomena at high speeds and in subatomic physics.23

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mechanics
Relative motion
A collision between two bodies can always be described in a frame of reference in which the total momentum is zero. This is the centre-of-mass (or centre-of-momentum) frame mentioned earlier. Then, for example, in the collision between two bodies of the same mass…
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A collision between two bodies can always be described in a frame of reference in which the total momentum is zero. This is the centre-of-mass (or centre-of-momentum) frame mentioned earlier. Then, for example, in the collision between two bodies of the same mass…
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motion
All motions are relative to some frame of reference. Saying that a body is at rest, which means that it is not in motion, merely means that it is being described with respect to a frame of reference that is moving together with the body. For…
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All motions are relative to some frame of reference. Saying that a body is at rest, which means that it is not in motion, merely means that it is being described with respect to a frame of reference that is moving together with the body. For…
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Uranus
The atmosphere
…the motion of the atmosphere relative to the rotating planet. At high latitudes on Uranus, this relative motion is in the direction of the planet’s rotation. At equatorial latitudes the relative motion is in the opposite direction. Uranus is like Earth in this regard. On Earth these directions are called…
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…the motion of the atmosphere relative to the rotating planet. At high latitudes on Uranus, this relative motion is in the direction of the planet’s rotation. At equatorial latitudes the relative motion is in the opposite direction. Uranus is like Earth in this regard. On Earth these directions are called…
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