There is no single, simple answer to that. The required speed would also depend on the rock's mass, its shape, and both the thickness and size of the window.
782 milesperhour
Rock+window=THERE YOU GO!
Call safelite or gO to a junkyard and find the window for cheep and look up how to put it in
People go up to a "window" && state their order
first you go to the rock then try to push the rock after that click on Hercules and he will kick the rock and it will break
They continue even today to break speed records approaching 300mph.
In Early Poptropica, go left to the towers and at the green tower, go up it until you reach the window with the flower. Break the window. (This costume might not be available.)
It can normally go 20 mph swimming and on land.
You do not break it. You need to get Oak's Letter and go there to trigger an event.
Hawks break there necks on your window and thye patterns are red and brown ok now go clean the hawk off your window bye
You have to go find a rock or something to throw at his window
first go to the first gym you beat and go to the left side go in and go down go in and then you will be in the ruins. you need the TM rock smash to break the rock by the trees then go in and press a and then you got a rare candy!