# Translation (physics)

A translation (also pure translation , linear movement ) is a movement in which all points of a physical system , e.g. B. a rigid body , experience the same displacement (see also: parallel displacement in geometry). At a given point in time, the velocities and accelerations of all points are identical. They move on parallel trajectories (see figure). This is to be distinguished from rotation , in which all points of the system or body move in a circle around a common axis. Any movement of a rigid body can be represented by superimposing translational and rotational movements.

A free body has three degrees of freedom of translation and three degrees of freedom of rotation in space . In the case of plane problems, the number of degrees of freedom is reduced to two for translation and one for rotation.

Special cases:

• The translation is straight if no accelerations occur transversely to the direction of movement.

Which accelerations occur in a specific case is determined by the external forces (see basic equation of mechanics ).

A body that performs a translation has an impulse in classical mechanics

${\ displaystyle {\ vec {p}} = m \, {\ vec {v}}}$ and a translational kinetic energy

${\ displaystyle E _ {\ mathrm {trans}} = {\ frac {1} {2}} \, m \, {\ vec {v}} \, ^ {2}}$ .

Here is the mass of the body and the speed of its center of gravity . ${\ displaystyle m}$ ${\ displaystyle {\ vec {v}}}$ ## Individual evidence

1. Peter Heinze: Technical Mechanics III Kinematics and Kinetics. (PDF; 879 kB) 2010, archived from the original on October 31, 2013 .