Question

When a block of mass M is suspended by a long

wire of length L, the length of the wire

becomes (L + l). The elastic potential energy

stored in the extended wire is ?​

Answer 1

Answer:

Explanation:

Explanation

Answer 2

★Given:-

• A block of mass M is suspended by a long  wire of length L.
• The new length of the wire  = (L + l).

★To find:-

• The elastic potential energy stored in the extended wire.

We know:

Elastic Potential energy per unit volume,

✦U = 1/2 ×stress ×strain

Let,

• volume of wire = V
• cross sectional area = A
• length of wire is = L  (Given)

Elastic potential energy = 1/2 × stress × strain × V

Also,

✦Stress = force applied/area  

            = Mg/A

✦Strain = change in length/original Length

           = l/L

Elastic potential energy:-

⇒1/2 × Mg/A × l/L × AL

⇒ 1/2 × Mg × l

⇒ 1/2 Mgl

Hence,

Elasticpotential energy stord in extended wire is 1/2Mgl

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