A bullet of mass 8 gram is fired into a block of mass 2,5 kg initially at rest at the edge of a frictionless table of height 1 m. The bullet remains in the block, and after impact the block lands a distance 2 m from the bottom of the table. Determine the initial speed of the bullet.

1 answer

first figure out how long it took the block to fall to the floor:
h = (1/2) g t^2
t = sqrt (2 h/g)
so it went 2 meters in t seconds
so the horizontal speed was
u = 2/t
NOW you have a conservation of momentum problem
u(2.5 + .008) = .008 v
solve for v