# Inertia when pulling on a rope [duplicate]

Imagine a fragile cord attached to a ceiling with its other side attached to a sphere. On the lower part another cord is atrached to the sphere. Now visualize you pull STRAIGHT downward on this cord. Where (i.e. at the upper or lower rope) will the cord break if you pull with much force quickly and where will it break if you pull for a longer duration with less magnitude? My assumption for the first, is that it would break at the lower rope, as it seems to me that inertia is the answer to this question here.