Question

❤❤❤Hey❤❤❤
Carries 5 Marks
Class 11 CBSE

Answer 1

Answer:

Explanation:

➡️Hookes law..

Stress is directly proportional to strain. the constant of proportionality is the modulus of elasticity..

➡️let the initial length of the wire be L1 and final length after stretching be L2

Now during a small elongation dx.

Work done by Tension will be -Fdx

Y=stress /strain = (F*L1)/Ax

F= (YA/L1)*x

thus total work done = integration of -Fdx from 0 to L2-L1

-(YA/L1)[x²/2]

-1/2(YA/L1)(L2-L1)²

potential energy stored = negative of work done = 1/2*(k)*x²

➡️Given that L=4 m

D=3 mmr

=1.5×10−3mm

=50 kgY

=7×1010 N/m2

g=9.8 m/s2

By Y=mgLπr2∆L∆L

=mgLπr2Y∆L

=50×9.8×43.14×(1.5×10−3)2×7×1010∆L=39.63×10−4 m∆L

=3.96 mm..

Hope it helps..