A wire is suspended from the ceiling and stretched under the action of a weight \(F\) suspended from its other end. The force exerted by the ceiling on it is equal and opposite to the weight.

(a) Tensile stress at any cross-section \(A\) of the wire is \(F/A.\)
(b) Tensile stress at any cross-section is zero.
(c) Tensile stress at any cross-section \(A\) of the wire is \(2F/A.\)
(d) Tension at any cross-section \(A\) of the wire is \(F.\)

 
Choose the correct option from the given ones:
1. (a) and (b) only
2. (a) and (d) only
3. (b) and (c) only
4. (a) and (c) only

Subtopic:  Stress - Strain |
 81%
Level 1: 80%+
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A rod of length \(l\) and negligible mass is suspended at its two ends by two wires of steel (wire \(A\)) and aluminium (wire \(B\)) of equal lengths (figure). The cross-sectional areas of wires \(A\) and \(B\) are \(1.0~\text{mm}^2\) and \(2.0~\text{mm}^2\) respectively.
\((Y_{\text{Al}}=70\times10^9~\text{N/m}^2\) and \(Y_{\text{steel}}=200\times10^9~\text{N/m}^2)\)
          

(a) The mass \(m\) should be suspended close to wire \(A\) to have equal stresses in both wires.
(b) The mass \(m\) should be suspended close to \(B\) to have equal stresses in both wires.
(c) The mass \(m\) should be suspended in the middle of the wires to have equal stresses in both wires.
(d) The mass \(m\) should be suspended close to wire \(A\) to have equal strain in both wires.
 
The correct statements are:
1. (b), (c) 3. (b), (d)
2. (a), (d) 4. (c), (d)
Subtopic:  Elasticity | Stress - Strain |
Level 3: 35%-60%
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