How do I move a part with BodyVelocity?

I have asked about how I could move a part with a script, but they told me to use BodyVelocity. How do I even use BodyVelocity? Anyways, here is what I learned:

local Cannon = script.Parent
local CannonBody = Cannon.Union
local Cannonball = game.Workspace.MiniGame1.Cannonball
local Wall = game.Workspace.MiniGame1.Wall
local GameStart = false
local x = 14.5
local y = 3.312
local z = -72.5

function Cannonfire()
	local Velocity = Instance.new("BodyVelocity")
	Velocity.Parent = Cannonball
	Velocity.MaxForce = Vector3.new(1e8, 1e8, 1e8)
	Velocity.Velocity = Vector3.new(1, .152, -1) * 5
end
wait(5)
GameStart = true
Cannonfire()

I'm trying to make a cannon shoot cannonballs, but the cannonball don't clone and/or move anywhere.

Any help is appreciated!

When a real cannon is fired, to put it simply, a single large amount of force is applied to the projectile in one single direction (the direction the barrel guides it in). That amount of force is applied once to the projectile, not continually or constantly, which is why the projectile eventually loses its initial energy from the launch (due to friction and gravity), and begins to form an arc. (Parabolic Motion).

Though you don't need to completely replicate how a real cannon fires, there are certain forces in real life that also exist in ROBLOX, like gravity.

You will want to apply the force to your projectile for a very short period of time and then remove the force, this will better simulate a real projectile.

Below are links to two important Wiki Pages that will greatly help you in this matter:

BodyMovers

Gravity

Just how much force should we use? Well, you will want to use a magnitude large enough to counter the force of gravity to a point where the object can become airborne and accelerate through space for a given time before reaching its apex and returning back to its original altitude.

"It is important to note that gravity in ROBLOX is an acceleration, a BodyForce object is a force, and that the BodyForce's force needs to be multiplied by the mass of the object in order to equal the gravitational pull on the object." - ROBLOX Wiki

How do we get the mass of an object? Well, we can simply use the :GetMass() method of a Part.

-- Example

local MyPart = game.Workspace.Part
local PartsMass = game.Workspace.Part:GetMass()
print(PartsMass)

I would recommend doing something along these lines:

local MyCannonBall = MyCannonBall:Clone()
local force = Instance.new("BodyThrust")	-- Thrust applies force local to part
force.Force = Vector3.new(x, y, z)
force.Location = Vector3.new(0,0,0)	
MyCannonBall.Anchored = false
MyCannonBall.Transparency = 1

MyCannonBall.Parent = game.Workspace
force.Parent = MyCannonBall
MyCannonBall.Transparency = 0
wait(0.1)
force:Destroy()

It's important to note that, for the above example, you would want to set and rotate the original anchored, transparent projectile in such a fashion that the axis in which the force is applied upon, is angled matching the angle of the barrel.

I hope this helps!

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