A block of mass m, attached to a spring of spring constant k, oscillates on a smooth horizontal table. The other end of the spring is fixed to a wall. The block has a speed v when the spring is at its natural length. Before coming to an instantaneous rest, if the block moves a distance x from the mean position, then

• A

  $\mathrm{x}=\sqrt{\mathrm{m}/\mathrm{k}}$

• B

  $\mathrm{m}=\frac{1}{\mathrm{v}}\sqrt{\mathrm{m}/\mathrm{k}}$

• C

  $\mathrm{x}=\mathrm{v}\sqrt{\mathrm{m}/\mathrm{k}}$

• D

  $\mathrm{x}=\sqrt{\mathrm{mv}/\mathrm{k}}$