Why do ships have propellers at the back?

Answer: Pushes water for forward thrust

Pushes water for forward thrust ✓ — Correct! Propellers work by pushing water backward (Newton's third law creates forward thrust). Placing them at the back (stern) allows them to push against undisturbed water flow. The propeller accelerates water backward, and the reaction force pushes the ship forward.

Balances weight distribution — Wrong. Weight balance isn't why propellers are at the back. They're positioned there for best thrust by pushing water in the direction opposite to desired movement.

Front propellers would damage bow hull — Wrong. Propellers spin underwater—they wouldn't damage the hull. Stern placement is about physics: pushing water backward creates forward thrust most efficiently.