My question is........

Why specific strength of materials is very high when they are in fibre size but lower when they are in bar form?

bcz in case of fibre structure arrangement is like crossed net ...so the material is capable of withstand the load from more no. of direction with more load capacity ,,,where as in case of bar structure,,arrangement is only in the form of linear arrangement only in one direction , so it leads to making the material strong in the direction of linear arrangement ..but it is very less capacity to withstand think he load in transverse direction of the arrangement.

i think this explanation can help u.

i can give u a real life example of that ...u must have seen any wooden structure , which are always made in such a way that grain distribution help the structure more in that direction which is more subjected to load,than t he other direction(i.e transverse direction)

thanks for your answer..........