A boy playing on the roof of a 10 m high building throws a ball with a speed of 10 m/s at an angle of 30^o with the horizontal. How far from the throwing point will the ball be at the height of 10 m from the ground?

$\left[\mathrm{g}=10\mathrm{m}/{\mathrm{s}}^2,\sin {30}^{\circ }=\frac{1}{2},\cos {30}^{\circ }=\frac{\sqrt{3}}{2}\right]$

 

• A

  8.66 m

• B

  5.20 m

• C

  4.33 m

• D

  2.60 m