hi..can anyone explain the ' breaking of strings' experiment show towards the end of lecture 6, in which the bottom string breaks even when it faces lesser force than the top one?

Question

hi..can anyone explain the ' breaking of strings' experiment show  towards the end of lecture  6, in which the bottom string breaks even when it faces lesser force than the top one?

anonymous · Answer

If you pull quickly, the large inertia of the block means that the bottom string accelerates faster than the upper one, so it breaks. The inertial of the block is not a factor if you pull slowly

anonymous · Answer

why isn't it a factor when being pulled slowly?

anonymous · Answer

When you pull the string slowly you are giving the block enough time to accelerate and thus transfer the forces to the top string.