What to do with tkinter.Menu tearoffcommand?

Question

I have a cascading tkinter.Menu which I create with tearoff=1. The tearoffcommand is passed two arguments:

• the name of the menu window (the window ID of the parent window?), which is a string like ".#!menu.#!menu#!menu3", and
• the name of the torn off menu window (the window ID of the new tear-off menu's root window), which is a string like ".tearoff1".

What can I do with this information? Here's what I'd like to do: By default, the torn-off menu gets placed at screen location (x=0, y=0), but I would like to place it at another (x,y) location.

How can I make this happen?

Sample code which attempts to use "nametowidget" as suggested:

import tkinter as tk

class App:
    def __init__(self, root):
        menubar = tk.Menu(root)
        menuA = tk.Menu(menubar, tearoff=0)
        menuB = tk.Menu(menubar, tearoff=0)
        menuC = tk.Menu(menubar, tearoff=1, tearoffcommand=self.onTearoff)
        menuC.add_command(label="Menu Row1")
        menuC.add_command(label="Menu Row2")
        menuC.add_command(label="Menu Row3")
        menubar.add_cascade(label="MenuA", menu=menuA)
        menubar.add_cascade(label="MenuB", menu=menuB)
        menubar.add_cascade(label="MenuC", menu=menuC)
        self.menubar = menubar
        root.config(menu=menubar)
        root.geometry("300x200")

    def onTearoff(self, wParent, wMenu):
        print("onTearoff(%s, %s)" % (wParent, wMenu)) # wMenu = ".tearoff1"
        w = root.nametowidget(wMenu) # KeyError: 'tearoff1'
        w.geometry("+50+50")

if __name__ == "__main__":
    root = tk.Tk()
    app = App(root)
    root.mainloop()