Examples of contraction in the following topics:
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- Objects that are moving undergo a length contraction along the dimension of motion; this effect is only significant at relativistic speeds.
- Length contraction arises due to the fact that the speed of light in a vacuum is constant in any frame of reference.
- Consequently, the length of the ruler will appear to be shorter in your frame of reference (the phenomenon of length contraction occurred).
- The effect of length contraction is negligible at everyday speeds and can be ignored for all regular purposes.
- Length contraction becomes noticeable at a substantial fraction of the speed of light (as illustrated in ) with the contraction only in the direction parallel to the direction in which the observed body is travelling.
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- Substances expand or contract when their temperature changes, with expansion or contraction occurring in all directions.
- The volumetric thermal expansion coefficient is the most basic thermal expansion coefficient. illustrates that, in general, substances expand or contract when their temperature changes, with expansion or contraction occurring in all directions.
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- Lorentz proposed that to understand the null result of the experiment objects moving through the aether contract by γ−1 = $\sqrt{1-v^2/c^2}$where γ is the Lorentz factor.
- Einstein's insight was that if the speed of light was the same for everyone moving uniformly, one would get the apparent "Lorentz" contraction without needing the aether through which light propagates or for the aether to contract objects.
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- The heart pumps blood through the body by contracting and relaxing, increasing and decreasing the pressure.
- The human heart will undergo over 3 billion contraction cycles during a normal lifetime.
- A complete cardiac cycle is one round of the heart pumping blood and consists of two parts: systole (contraction of the heart muscle) and diastole (relaxation of the heart muscle).
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- Just as nerve impulses are transmitted by depolarization and repolarization of an adjacent membrane, the depolarization that causes muscle contraction can also stimulate adjacent muscle cells to depolarize (fire) and contract.
- Thus, a depolarization wave can be sent across the heart, coordinating its rhythmic contractions and enabling it to perform its vital function of propelling blood through the circulatory system.
- The P wave is generated by the depolarization and contraction of the atria as they pump blood into the ventricles.
- Arterial blood pressure varies with each part of the heartbeat, with systolic (maximum) pressure occurring closely after the QRS complex, signaling the contraction of the ventricles.
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- Although all of the heart's cells have the ability to generate the electrical impulses (or action potentials) that trigger cardiac contraction, the sinoatrial node normally initiates it, simply because it generates impulses slightly faster than the other areas with pacemaker potential .
- Purkinje fibers allow the heart's conduction system to create synchronized contractions of its ventricles, and are therefore essential for maintaining a consistent heart rhythm.
- During the ventricular contraction portion of the cardiac cycle, the Purkinje fibers carry the contraction impulse from both the left and right bundle branch to the myocardium of the ventricles.
- This causes the muscle tissue of the ventricles to contract, thus enabling a force to eject blood out of the heart.
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- Materials which contract or maintain their shape with increasing temperature are rare.
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- Eventually, when all stars have died, all forms of potential energy have been utilized, and all temperatures have equalized (depending on the mass of the universe, either at a very high temperature following a universal contraction, or a very low one, just before all activity ceases) there will be no possibility of doing work.
- However, whether the universe contracts and heats up, or continues to expand and cools down, the end is not near.
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- Surface tension is a contractive tendency of the surface of a liquid that allows it to resist an external force.
- This creates some internal pressure and forces liquid surfaces to contract to the minimal area.