Thread: Physics question

Could you please urgently help me to solve the following question. I have to turn it in until tomorrow (monday) night.
Thank you.

A mass of 1019Kg is supported by two wires A and B each made of a different material. Before loading the wires are of equal length. After loading they are still of equal length. Find the load carried by each wire.


Wire Diameter E

Wire A 1 mm 206,000 Nmm 2

Wire B 2 mm 116,000 Nmm 2

Originally Posted by salvavida

Could you please urgently help me to solve the following question. I have to turn it in until tomorrow (monday) night.
Thank you.

A mass of 1019Kg is supported by two wires A and B each made of a different material. Before loading the wires are of equal length. After loading they are still of equal length. Find the load carried by each wire.


Wire Diameter E

Wire A 1 mm 206,000 Nmm 2

Wire B 2 mm 116,000 Nmm 2

You know that the sum of the loads/tensions on/in the two wires sums to
1019g Newtons:



and that the original lengths and the extensions of the wires are equal.

If and are the Youngs moduli of the two wires (Presumably your 's)
and and their crossectional areas then if and are the
tensions in the two wires we have:



and:



but the original length and the extension of each wire are
equal so:

.

Equations and should allow you to solve
for the two loads and

RonL

Dear RonL,

thanks a lot for your reply, but could you please give me a bit more informatin on the solution, as I have not figured out the path to the answer yet.
Thanks,
Salvavida

We found that:

.

plugging the values of Youngs modulus for the two materials, and the
crossectional areas gives:

,

so:

.

But we also had:

,

so substituting from :

,

solving:

,

and so:

.

RonL