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translational motion (translation)

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поступальний рух

Fig. 1.12

The motion of a rigid body when any straight line, fixed within the body, remains parallel to its original position is called translational motion.

Let a rigid body move translational (Fig. 1.12). Any two points A and B are connected by vector . Its modulus is constant, because a rigid body is considered. The direction of this vector is not also changed, because a rigid body moves translational.

So if a rigid body moves translational:

= const.

Position of points A and B arestated by the position-vectors and . Fig. 1.12 demonstrates the relationship between these vectors, and vector :

Let equation of motion of point A be known as:

Then equation of motion of point B is:

Consequently

Point B moves as point A, and the separation between them equals .

The trajectories of these points are equidistant. They can be united by a simple parallel displacement.

The velocity of point B is determined by equation of motion of this point:

But as = const

, and

then

.

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