Question

A bullet of mass m moving with velocity v strikes a block of mass M at rest and gets embedded into it. The kinetic energy of the composite block will be -

• A. $\frac { 1 } { 2 }$mv² × $\frac { \mathrm { m } } { ( \mathrm { m } + \mathrm { M } ) }$
• B. $\frac { 1 } { 2 }$mv² ×
• C. $\frac { 1 } { 2 }$mv² × $\frac { ( M + m ) } { M }$
• D. $\frac { 1 } { 2 }$Mv² ×

Answer 1

Answer: (A)

$\frac { 1 } { 2 }$mv² × $\frac { \mathrm { m } } { ( \mathrm { m } + \mathrm { M } ) }$

Answer 2

mv = (M + m) v'

v' =

K.E. of composite block = $\frac { 1 } { 2 }$(M + m) v'²

= $\frac { 1 } { 2 }$ (M + m) × =