Haow i set bullet speed on collision?

hi, i'm creating a platform game and i have set bullet speed to default a 900.

Haow i can set bullet speed at 2500 on collision whith another object?

I can't use animation

on collision -> set animation

if animation play set bullet speed to 2500 i'ts ok but i have set other animation...

on collision whith bullet set animation fire, and on collision whit shoe set bullet speed to 2500 don't go....

On collision -> set bullet speed

using "set animation" changes which sprite animation is playing, not the speed of the bullet