Calculate the recoil velocity of a gun having mass equal to 5 kg, if a bullet of 25 g acquires the velocity of 500 m s − 1 after firing from the gun. A. 25 m s − 1 B. 2.5 m s − 1 C. 10 m s − 1 D. 5 m s − 1

Question

Calculate the recoil velocity of a gun having mass equal to 5 kg, if a bullet of 25 g acquires the velocity of   500  m      s          −      1       after firing from the gun.  A.   25  m      s          −      1       B.   2.5  m      s          −      1       C.   10  m      s          −      1       D.   5  m      s          −      1

Brian Blackburn · Accepted Answer

Given Data: mass of bullet,       m    1    =  25  g  =  0.025  k  g  velocity of bullet before firing,       u    1    =  0  m      s          −      1        velocity of bullet after firing,       v    1    =  500  m      s          −      1        mass of gun,      m    2    =  5  k  g  velocity of gun before firing,      u    2    =  0  m      s          −      1       Let velocity of gun after firing be,  v2  From law of conservation of momentum,       m    1        u    1    +      m    2        u    2    =      m    1        v    1    +      m    2        v    2         m    1    ×  0  +      m    2    ×  0  =  0.025  ×  500  +  5  ×      v    2     ⟹  0  =  12.5  +  5      v    2    ⟹      v    2    =  −      12.5    5    =  −  2.5  m      s          −      1      This indicates that the gun recoils, or moves in the opposite direction of the bullet.Thus, recoil velocity of gun is equal to   2.5  m      s          −      1        Here, the negative(- ve) sign shows that gun moves in the opposite direction of bullet.

Calculate the recoil velocity of a gun having mass equal to 5 kg, if a bullet of 25 g acquires the velocity of 500 ms^(−1) after firing from the gun. A. 25 ms^(−1) B. 2.5 ms^(−1) C. 10 ms^(−1) D. 5 ms^(−1)

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