Original Post
Ok, I have been working on a 2d space game. I have 2d acceleration working fine, but now I need to scale a vector down based on time. vx,vy - Velocity accel - Acceleration constant dt - Delta time posx,posy - Object position rotation - Object Rotation vx += accel * dt * cos(rotation); vy += accel * dt * sin(rotation); posx += vx * dt; posy += vy * dt; What I need to do now is slow down the object by a constant factor, but based on time. Is there some kind of formula or equation for this? vx *= deceleration_constant;