COMEDK · Physics · 10. Mechanical Properties of Solids
Two wires are made of the same material and have the same volume. The first wire has cross-sectional area \(A\) and the second wire has cross-sectional area \(3 A\). If the length of the first wire is increased by \(\Delta l\) on applying a force \(F\), how much force is needed to stretch the second wire by the same amount?
- A 4F
- B 9F
- C 6F
- D F
Answer & Solution
Correct Answer
(B) 9F
Step-by-step Solution
Detailed explanation
Let the length and area of the first wire be \(L_1\) and \(A_1 = A\). Let the length and area of the second wire be \(L_2\) and \(A_2 = 3A\). Since the volumes are equal, \(V_1 = V_2\), we have \(A_1 L_1 = A_2 L_2\). Substituting the given values, \(A L_1 = 3A L_2\), which…
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