1. The problem statement, all variables and given/known data Tell me what is wrong with this question- A donkey which has heard of Newtons third law but not understood it very well refuses to pull a cart attached to it because it argues that: ' If i pull on the cart with a certain force, Newton's third law would imply an equal but opposite force, which would then mean that the total force on the cart is zero, and so it will not move. so why waste my effort?i wont pull'. What's wrong with the donkey's argument? 3. The attempt at a solution Is it because there is no reaction to the cart. for example the space shuttle example is a gud one. the downward thrust produces an equal upward trust. there is only the reaction with the ground the cart has which is friction so the donkey will be able to pull on it since the friction force is very small and there is no reaction with the cart.