Question

The breaking stress of aluminium is 7.5x 107 N/m2 . Find the greatest length of aluminium wire that can hang vertically without breaking. Density of aluminium is 2.7x103 kg/m3 .

Answer 1

Breaking stress of  = σ=7.5x 10⁷ N/m2
density of Aluminium= ρ =2.7 X 103 kg/m3
g=10m/s²
let the maximum length that can be hung vertically be L
 Let CSA=A
volume of wire=AL
mass of wire=ρAL
when hung force acting on the wire
F=ρALg
F/A=ρlg
 σ= ρlg
now maximum, stress that wire can withstand σ=σb
so,
ρLg=σb  =7.5x 10⁷
L=7.5x 10⁷/ρg
=7.5x 10⁷/2.7x10³x10
L=2.77x10³ m

Answer 2

Answer:

2.83

Explanation:

See the attachment below