make wheel rotate speed faster or slower with magnitude?

local num = -0.1 local rs = game:GetService("RunService")

So basically i want the num to decrease as the part gets closer to its destination basically a car slowing down!

my attempt

spawn(function()
while true do
num = (workspace.wheel.Position - workspace.stop.Position).magnitude
wait()
end
end)

for i = 1,100 do
workspace.wheel.CFrame = workspace.wheel.CFrame * CFrame.fromEulerAnglesXYZ(num,0,0)
rs.Heartbeat:Wait()
end