A small sphere of mass m = 2kg moving with a velocity $\stackrel{-}{\mathrm{u}}=4\widehat{\mathrm{i}}-7\widehat{\mathrm{j}}\mathrm{m}/\mathrm{s}$ collides with a smooth wall and returns with a velocity $\overline{\mathrm{v}}=-\widehat{\mathrm{i}}+3\widehat{\mathrm{j}}\mathrm{m}/\mathrm{s}$ . The magnitude of the impulse received by the ball is

• A

  5kg ms^-1

• B

  $10\sqrt{5}{\mathrm{kgms}}^{-1}$

• C

  20 kg ms^-1

• D

  15kg ms^-1