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The line of action is shown as the vertical dotted line. It extends in both directions relative to the force vector, but is most useful where it defines the moment arm. In physics , the line of action (also called line of application ) of a force ( F → ) is a geometric representation of how the force is applied.
The moment of force, or torque, is a first moment: =, or, more generally, .; Similarly, angular momentum is the 1st moment of momentum: =.Momentum itself is not a moment.; The electric dipole moment is also a 1st moment: = for two opposite point charges or () for a distributed charge with charge density ().
If the force is perpendicular to the displacement vector r, the moment arm will be equal to the distance to the centre, and torque will be a maximum for the given force. The equation for the magnitude of a torque, arising from a perpendicular force: = ().
The kinetic energy equations are exceptions to the above replacement rule. The equations are still one-dimensional, but each scalar represents the magnitude of the vector, for example, = + +. Each vector equation represents three scalar equations.
A stronger mathematical definition is to use vector algebra, since a quantity with magnitude and direction, like the dipole moment of two point charges, can be expressed in vector form = where d is the displacement vector pointing from the negative charge to the positive charge.
Angular momentum (sometimes called moment of momentum or rotational momentum) is the rotational analog of linear momentum. It is an important physical quantity because it is a conserved quantity – the total angular momentum of a closed system remains constant. Angular momentum has both a direction and a magnitude, and both are conserved.
The time to reach the finishing line is longer for objects with a greater moment of inertia. ( OGV version ) The moment of inertia about an axis of a body is calculated by summing m r 2 {\displaystyle mr^{2}} for every particle in the body, where r {\displaystyle r} is the perpendicular distance to the specified axis.
In electromagnetism, the magnetic moment or magnetic dipole moment is the combination of strength and orientation of a magnet or other object or system that exerts a magnetic field. The magnetic dipole moment of an object determines the magnitude of torque the object experiences in a given magnetic field. When the same magnetic field is applied ...