No its doesnt
The damage from spikes is calculated by how many you put and flying and levitate Pokemon will not be damaged by spikes.
1 layer will do 1/8
2 layers will do 1/6
3+ layers will do 1/4
Stealth rocks depends on the Pokemon type.
Type Effectivness Damage
x0.25 Effective 1/32 of Max HP (3.125%)
x0.5 Effective 1/16 of Max HP (6.25%)
x1 Effective 1/8 of Max HP (12.5%)
x2 Effective 1/4 of Max HP (25%)
x4 Effective 1/2 of Max HP (50%)
So its impossible to K.O a full health Pokemon with entry hazard
Hope I helped! :D