Question

A steel wire of cross-sectional area 3 x 10-6 m2
can withstand a maximum strain of 10-3. Young's
modulus of steel is 2 x 1011 N m-2. The maximum
mass the wire can hold is (take g = 10 m s-2)
(1) 40 kg
(2) 60 kg
(3) 80 kg
(4) 100 kg​

Answer 1

The maximum  mass of the wire is 60 Kg.

Option (2) is correct.

Explanation:

As we know that:

Young's modulus "Y" = Stress / Strain

= max ∙ strain

Since => strain = Stress / Y

= (max ∙ stress) / Y

Y = mg / A x Strain

2 x 10^11 = m x 10/ 3 x 10^-6 x 10^-3

2 x 10^11 x 3 x 10^-9 = m x 10

600 = m x 10

m = 600/10

m = 60 Kg

Thus the maximum  mass of the wire is 60 Kg.

Answer 2

Answer:

max mass=60 kg

Explanation:

Young's modulus "Y" = Stress / Strain

= max ∙ strain

Since => strain = Stress / Y

= (max ∙ stress) / Y

Y = mg / A x Strain

2 x 10^11 = m x 10/ 3 x 10^-6 x 10^-3

2 x 10^11 x 3 x 10^-9 = m x 10

600 = m x 10

m = 600/10

m = 60 Kg

Thus the maximum  mass of the wire is 60 Kg