Bullet object slow down over time.

Hi, Thanks for looking at my question.

Does any one know how i can achieve my effect?

Let me explain the situation -

I have a bullet object,

Every tick its moving at a speed of 400.

Basically If the players y is in the stars region and is at a angle of 90-90 degrees, I want the bullets speed to decrease to zero smoothly, Then when at its 0 degrees then tween its speed back to 400.

Does anyone show me how to do this?

I think its meant to be using lerp?

But im not so sure on what im supposed to do with it..