Deflection (physics)

An object hitting a surface is an example of deflection.

Inphysics,deflectionis a change in a moving object'svelocity,hence itstrajectory,as a consequence of contact (collision) with a surface or the influence of anon-contact force field.Examples of the former include a ball bouncing off the ground or a bat; examples of the latter include abeam of electronsusedto produce a picture,or therelativistic bending of light due to gravity.

Deflective efficiency

An object'sdeflective efficiencycan never equal or surpass 100%, for example:

a mirror will neverreflectexactly the same amount of light cast upon it, though it may concentrate the light which is reflectedinto a narrower beam.
on hitting the ground, a ball previously infree-fall(meaning no force other thangravityacted upon it) will never bounce back up to the place where it first started to descend.

This transfer of some energy into heat or other radiation is a consequence of the theory ofthermodynamics,where, for every such interaction, some energy must be converted into alternative forms of energy or is absorbed by the deformation of the objects involved in the collision.

Deflective efficiency

See also