angular momentum

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angular momentum

MRI
The cross product of the ordinary momentum of a particle and its position vector, running from the axis of rotation to the body whose momentum is being determined.

In absence of external forces, the angular momentum (AM) remains constant; therefore, a rotating body tends to maintain the same axis of rotation. When torque is applied to a rotating body, the resulting change in AM results in precession. Momentum involved in the rotation of a body about an axis is conserved, as is ordinary momentum. Atomic nuclei possess an intrinsic AM known as “spin”, which is measured in multiples of Planck’s constant.

an·gu·lar mo·men·tum

(ang'gyŭ-lăr mō-men'tŭm)
The spin of MR active nuclei, which depends on the balance between the number of protons and neutrons in the nucleus.
References in periodicals archive ?
The NJM patterns observed during swing leg contact phase (ankle plantar flexor, knee extensor, and hip flexor) were similar to those tasks requiring forward angular impulse generation [22,25-26,40].
During the forward fall recovery, a set of ankle plantar flexor, knee flexor, and hip extensor NJMs was used for neutralizing the forward angular impulse during the impact phase [5].
Mechanisms used by the support leg to regulate forward angular impulse during backward fall recovery require further investigation.
Understanding the regulation of backward angular impulse by generating forward angular impulse allows clinicians with basic knowledge to explore new therapy strategies to improve backward recovery.
Regulation of angular impulse, by stepping strategies, is an essential part of fall recovery.
For the support leg, the inability to sufficiently redirect the GRF relative to the COM observed in older adult fallers is attributed to their inability to redistribute the lower-limb NJMs to regulate the angular impulse. An individual can generate needed backward angular impulse for a forward fall recovery by generating a set of relatively large hip extensor NJMs and small knee extensor or knee flexor NJMs by activating the gluteus maximus and hamstrings.