Leftover...

The Lagrangian,

$L=T-V$

a particle enters a field with certain kinetic energy.  It acquires potential energy at the expense of its $KE$.  What happens to the $L$eftover energy?

Equally admissible,

$L=V-T$

a particle of certain potential energy in a field is set off acquiring kinetic energy.  It acquires $KE$ at the expense of $PE$.  What happens to the $L$eftover energy?

Good night.