364 



INDEX 



Transmissibility of force, 94. 

 Triangle, of velocities, 10. 

 Triangular lamina, center of gravity 

 of, 121. 



Uniformity, of nature, 1. 

 Unit, of velocity, 6 ; of force, 30 ; of 

 work, 145. 



Variation, of value of gr, 200 ; of ter- 

 restrial latitude, 310. 



Vectors, 16 ; in one plane, 16 ; in space, 

 19. 



Velocity, uniform and variable, 6 ; 

 average, 6 ; composition of, 7 ; mo- 

 ment of, 274 ; angular, 286. 



Vibrations, 348, 353. 



Virtual work, principle of, 155. 



Weight, of a particle, 42 ; of a system 

 of particles, 118. 



Wheel and axle, 65. 



Work, measurement of, 145 ; against a 

 variable force, 148 ; of stretching a 

 string, 148 ; represented by an area, 

 150 ; against an oblique force, 152 ; 

 performed against gravity, 153 ; per- 

 formed by a couple, 154 ; principle 

 of virtual, 166; performed by an 

 impulse, 235. 



Wrench, 107. 



