A particle is projected at an angle of 60⁰ above the horizontal with a speed of 10 m/s. After some time the direction of its velocity makes an angle of 30° above the horizontal. The speed of the particle at this instant is

• A

  $\frac{5}{\sqrt{3}}\mathrm{m}/\mathrm{s}$

• B

  $5\sqrt{3}\mathrm{m}/\mathrm{s}$

• C

  5 m/s

• D

  $\frac{10}{\sqrt{3}}\mathrm{m}/\mathrm{s}$