A steel wire of length 4.0 m is stretched by 2.0 mm. The cross-sectional area of the wire is 2.0 mm2. If Young's modulus of steel is 2.0 × 10 11 N / m 2 , thenA) the energy density of wire is 2.5 × 10 4 J / m 3 . B) the elastic potential energy stored in the wire is 0.20 J. C) the energy density of wire is 2.0 × 10 4 J / m 3 . D) the elastic potential energy stored in the wire is 0.30 J.

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A steel wire of length 4.0 m is stretched by 2.0 mm. The cross-sectional area of the wire is 2.0  mm2. If Young&#039;s modulus of steel is   2.0  ×      10          11           N      /        m    2  , thenA) the energy density of wire is   2.5  ×      10    4       J      /        m    3  . B) the elastic potential energy stored in the wire is 0.20 J.  C) the energy density of wire is   2.0  ×      10    4    J      /        m    3  .  D) the elastic potential energy stored in the wire is 0.30 J.

rozchytatm0p · Accepted Answer

The correct options areA) the energy density of wire is   2.5  ×      10    4       J      /        m    3  .B B, the wire has a 0.20 J elastic potential energy.Here, l=4.0 m;  △  l  =  2  ×      10          −      3           m  ;     a  =  2.0  ×      10          −      6               m    2    Y  =  2.0  ×      10          11           N      /        m    2  The tension of stretched wire&#039;s energy  u  =      1    2    ×   stress   ×   strain   =      1    2    Y  (   strain       )    2      =      1    2    ×  2.0  ×      10          11        ×  (  2  ×      10          −      3            /    4      )    2      =  0.25  ×      10    5    =  2.5  ×      10    4       J      /        m    3    Elastic potential energy = energy density   ×  v  o  l  u  m  e  2.5  ×      10    4    ×  (  2.0  ×      10          −      6        )  ×  4.0  J    =  20  ×  10  −  2  =  0.20     J

A steel wire of length 4.0m is stretched by 2.0 mm. The cross-sectional area of the wire is 2.0 mm^2. If Young's modulus of steel is 2.0 xx 10^(11) N/m^2

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