d
આંતરિક બળો દ્વારા થતું કાર્ય \( = \,\,\Delta {\text{KE}}\,\, = \,\,{\text{2}}\,\,\left( {\frac{{\text{1}}}{{\text{2}}}\,\,m{v^2}\,\, - \,\,0} \right)\)
\( = \,\,2\,\,\left( {\frac{1}{2}\,\, \times \,\,2\,\, \times \,\,25\,\, - \,\,0} \right)\,\, = \,\,50\,\,J\)