Rc. Zhang et al., Effects of non-conservative forces on Lie symmetries and conserved quantities of a Lagrange system, CHIN PHYS, 9(11), 2000, pp. 801-804
Non-conservative forces are exerted on a Lagrange system. Their effects on
Lie symmetries, structure equation and conserved quantities of the system a
re studied. It can be seen that some Lie symmetries disappear and some new
Lie symmetries emerge. Under certain conditions, some Lie symmetries will s
till remain present.