A steel wire having a radius of \(2.0\) mm, carrying a load of \(4\) kg, is hanging from a ceiling. Given that \(g=3.1\pi~\text{m/s}^{2}\), what will be the tensile stress that would be developed in the wire?
1. \(5.2\times10^{6}~\text{N/m}^{2}\) 2. \(6.2\times10^{6}~\text{N/m}^{2}\)
3. \(4.8\times10^{6}~\text{N/m}^{2}\) 4. \(3.1\times10^{6}~\text{N/m}^{2}\)
Subtopic:  Stress - Strain |
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A block of mass \(M\) is attached to a prop on a smooth horizontal surface of a truck by means of a wire of length \(L,\) cross-section \(\alpha.\) Young's modulus of elasticity of the material of the wire is \(Y.\) The truck accelerates forward with an acceleration \(a=\dfrac{g}{2}.\) The change in length of the wire is:
1. \({\dfrac{MgL}{\alpha Y}}\) 2. \({ \dfrac{MgL}{2\alpha Y}}\)
3. \({\dfrac{2MgL}{\alpha Y}}\) 4. \({ \dfrac{MgL}{4\alpha Y}}\)
Subtopic:  Stress - Strain |
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Three blocks of masses \(1~\text{kg},2~\text{kg},2~\text{kg}\) lie in a line on a smooth horizontal plane, connected by two horizontal metallic wires (of negligible mass) – \(I\) & \(II.\) A horizontal force of \(10~\text{ N}\) acts on the \(1~\text{kg}\) block, as shown.
                           
The cross-sectional area \((A),\) length \((L)\) and Young's moduli \((Y)\) of the wires are related by:    \(A_I=2A_{II}\\ L_I=2L_{II}\\ Y_I=2Y_{II}\)
The ratio of the stresses in the wires (wire \(\mathrm I\)/\(\mathrm{II}\)) is:
1. \(1\)
2. \(2\)
3. \(\dfrac12\)
4. \(4\)
Subtopic:  Stress - Strain |
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A uniform metallic wire is elongated by \(0.04\) m when subjected to a linear force \(F\). The elongation, if its length and diameter are doubled and subjected to the same force will be:

1. \(1\) cm 2. \(2 \) cm
3. \(3\) cm 4. \(6\) cm
Subtopic:  Stress - Strain |
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A wire of length \(l,\) cross-sectional area \(A\) is pulled as shown. \(Y\) is Young’s modulus of wire. The elongation in wire is:
(\(F=100\) N, \(A=10\) cm2\(l=1\) m, \(Y=5\times10^{10}\) N/m2)

   
1. \(10^{-6}\) m
2. \(10^{-5}\) m
3. \(2\times10^{-6}\) m
4. \(2\times10^{-5}\) m
Subtopic:  Stress - Strain |
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Level 1: 80%+
JEE
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Three blocks of masses \(1~\text{kg},2~\text{kg},2~\text{kg}\) lie in a line on a smooth horizontal plane, connected by two horizontal metallic wires (of negligible mass) – \(I\) & \(II.\) A horizontal force of \(10~\text{ N}\) acts on the \(1~\text{kg}\) block, as shown.
                           
The cross-sectional area \((A),\) length \((L)\) and Young's moduli \((Y)\) of the wires are related by:    \(A_I=2A_{II}\\ L_I=2L_{II}\\ Y_I=2Y_{II}\)
The ratio of the strains in the wires (wire \(\mathrm{I}\)/wire \(\mathrm{II}\)) is:
1. \(1\)
2. \(2\)
3. \(\dfrac12\)
4. \(4\)
Subtopic:  Stress - Strain |
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A rod is fixed at one end and other end is pulled with force \(F = 62.8\text{ kN},\) Young’s modulus of rod is \(2 × 10^{11} \text{ N/m}^2.\) If the radius of cross-section of rod is \(20\text{ mm}\) the strain produced in rod is
 
1. \(2.5\times10^{-3}\)
2. \(2.5\times10^{-4}\)
3. \(2.0\times10^{-3}\)
4. \(2.0\times10^{-4}\)
Subtopic:  Stress - Strain |
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A body of mass \(m=10\) kg is attached to a wire of length \(0.3\) m. Its breaking stress is \(4.8\times 10^{7}\) N/m2. The area of the cross-section of the wire is \(10^{-6}\) m2. What is the maximum angular velocity with which it can be rotated in the horizontal circle?
1. \(4\) rad/s
2. \(8\) rad/s
3. \(1\) rad/s
4. \(2\) rad/s
Subtopic:  Stress - Strain |
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The breaking stress of a wire depends on:

1. material of the wire
2. length of the wire
3. radius of the wire
4. shape of the cross-section
Subtopic:  Stress - Strain |
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Consider two wires \(A\) and \(B\) which are made of same material. The diameter of \(A\) is four times larger than \(B.\) If they are stretched by same load, then the stress on \(B\) is:
1. equal to that on \(A\)
2. sixteen times that on \(A\)
3. twice that on \(A\)
4. half that on \(A\)
Subtopic:  Stress - Strain |
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