how does newtons 3rd law apply to a catapolt?

Question

i need to know the motion and force

Answer 1

Newton's third law isn't about motion. It says that if a force exists (in this case the force on the ball, or whatever), then an equal and opposite force must exist on whatever causes the first force. In this case the ball is forced forwards, so the catapult is forced backwards. In practice your hand also exerts a force on the catapult, so it does not go backwards, but there is a (small) force on you.