Abullet, m = 0.500 kg, traveling with some initial velocity strikes and embeds itself

5 m/s

Explanation:

mass of bullet, m = 0.5 kg

initial velocity of bullet is u.

mass of pendulum, M = 9.50 kg

height raised, h = 1.28 m

The kinetic energy of the bullet and pendulum system is equal to the potential energy of the system

Let vf be the final velocity after the impact

KE = PE

1/2 (M + m) Vf^2 = (M + m) x g x h

vf^2 = 2 x 9.8 x 1.28 = 25.088

vf = 5 m/s

Thus, the final speed of the combined mass system after the impact s 5 m/s.  

If I'm reading this correctly, then it should be 5 meters.

If you look at the graph, you will see that they walked 5 meters on the 5 second mark and then stopped. On the 6 second mark, they still didn't move so they are still on that 5 meter mark.