My velocity scripts isn't working ? Im using magnitude for the velocity

The script works , it spawns a part but the velocity script isn't working for some reason??

local ray = Ray.new(script.Parent.Position,Vector3.new(0,0,-40))
local Peashooter = script.Parent.Parent
local Damage = 20
local Folder = workspace.Folder
local main = script.Parent
local Debris = game:GetService("Debris")
local plr = game.Players

while wait(2.5)do
    local hit,position = workspace:FindPartOnRayWithIgnoreList(ray,{script.Parent,Folder})
    if hit then 


        local k = Instance.new("Part", game.workspace)
        k.Anchored = false
        k.CFrame = main.CFrame + Vector3.new(0,0,0)
        k.Size = Vector3.new(1,1,1)
        k.Shape = "Ball"
        k.BrickColor = BrickColor.new("Bright green")
        k.Material = "Neon"
        k.Parent = Folder
        k.CanCollide = false


        k.Velocity = main.CFrame.LookVector * (hit.Position - main.Position).Magnitude

Debris:AddItem(k,5.5)

 k.Touched:Connect(function(hit)
    local Enemy = hit.Parent.Zombie
   Enemy:TakeDamage(Damage)
k:Destroy()

 end)
    end
    end