Catapult is offensive, Mangonel is defensive.
Mangonel's are placed on top of big towers.
Don't be a Merc Haboe, start to read history books
What kind of history books you read? "The siege of legoland" ?
Mangonel is a siege machine which was used to shot multiple smaller stones at once.
Catapults, same as trebuchets were used for - actually who doesn't knows that..
Catapults were oftenly spotted on walls and towers, same as trebuchets.
All.