UNITS AND DEFINITIONS RELATED TO BIOMECHANICAL AND ELECTROMYOGRAPHICAL MEASUREMENTS - Biomechanics and Motor Control of Human Movement - page 365

TABLE B.2 (Continued)

Name of

Physical Quantity Symbol SI Unit Definition

Power P watt (W) Rate at which work is done or

energy is expended. The power
generated by a force is the dot
product of the force and the
velocity at the point of
application of the force ( P

= F

· V ). The power generated by

a moment is the dot product of
the moment and the angular
velocity of the rigid body ( P

=

M · ω ).

Coefficient of friction μ — For two objects in contact over a

surface, the ratio of the contact
force parallel to the surface to
the contact force perpendicular
to the surface.

m − 2 Coefficient of viscosity η N · s · Resistance of a substance to

change in form; calculated by
the ratio of shear stress to its
rate of deformation.

Electrical charge q coulomb (C) Quantity of a negative or positive

charge on any mass. The
charge on an electron or proton
is 1.602 10 − 19 C, or 1

× · C, has

the charge of 6.242 ×

10 18 electrons or protons [1 A
(ampere) = 1C · s − 1 ].

Voltage, electrical
potential

E volt (V) Potential for an electrical charge

to do work (1 V = 1J · C − 1 ).

Electrical resistance R ohm ( ) Property of a conducting element

that opposes the flow of
electrical charge in response to
an applied voltage (1 = 1V
· A − 1 ).

Electrical capacitance C farad (F) Property of an electrical element

that quantifies its ability to
store electrical charge. A
capacitance of 1 F means that
1 C of charge is stored with a
voltage change of 1 V (1 F =

V − 1 ).

1C ·