How to push a player back?

So, I'm doing a code that pushes all nearby players back away from the character, but whenever I do it, it does nothing. Any thoughts? I have a RemoteEvent in ReplicatedStorage as well named "push", and the serverscript is definitely running. Server Script:

ReplicatedStorage = game:GetService("ReplicatedStorage")

 remoteEvent = ReplicatedStorage:WaitForChild("push")

 function onCreatePart(orig, plr, char)
	local Players = game:GetService("Players")
	for i, player in pairs(Players:GetPlayers()) do
		if ((player.Character.HumanoidRootPart.Position - char.HumanoidRootPart.Position).magnitude <= 100) and (player.Name ~= plr.Name) then
			 local torso = player.Character.UpperTorso
			local back = Vector3.new(0,0,-100)
			 player.Character.HumanoidRootPart.Velocity = back
		end
	end            
end
remoteEvent.OnServerEvent:Connect(onCreatePart)

LocalScript:

local ReplicatedStorage = game:GetService("ReplicatedStorage")
local test = true
local remoteEvent = ReplicatedStorage:WaitForChild("push")
local player = game.Players.LocalPlayer
    local mouse = player:GetMouse()

mouse.KeyDown:connect(function(key)
    if test == true then
            if key == "x" and player.TeamColor == BrickColor.new("Mulberry") then
            local plr = player
            local char = player.Character
            remoteEvent:FireServer(plr, char)
            test = false
            wait(15)
            test = true
        end
        end
    end)