Bullet hell. Just before colliding with a block of mass \( M=4.00[\mathrm{~kg}] \), a bullet with mass \( m=25.0[\mathrm{~g}] \) move with speed \( v=840 \). [m/s]. After collision, the block and bullet moved as one on a frictionless surface and falls a height \( h=2.75[\mathrm{~m}] \). What is its speed as it hits the ground?
724 [m/s]
27.9 [m/s]
9.01 [m/s]
\( 7.69[\mathrm{~m} / \mathrm{s}] \)