parallelogram of forces
力平行四边形

• phototelephony
• phototelescope
• photo-theodolite
• phototherapeutics
• phototherapy
• photothermionic image converter
• phototimer
• phototiming
• phototransistor
• phototransistors
• phototransmutation
• phototriode
• phototroller
• phototron
• phototrop
• phototropic
• phototropic vision
• phototropism
• phototube
• phototubes
• phototype
• phototypesetter
• photounit
• photovalue
• photovaoltaic