A 4.1 g dart is fired into a block of wood with a mass of 20.2 g. The wood block is initially at rest on a 1.2 m tall post. After the collision, the wood block and dart land 2.6 m from the base of the post. Find the initial speed of the dart.

Answer 1

momentum is conserved.

Momentum before=momentum after
4.1*V=(4.1+20.2)Vblock

Now solve for vblock.
time to fall down: 1.2=1/2 g t^2 solve for time t.
then horizontal distance=Vbloci*tiem
solve for Vblock.

Now, using the first equation, solve for V, the speed of the dart.

Answer 2

you are wrong.