Answer:
The value of speed of wooden block at the instant after the collision
262.41

Step-by-step explanation:
Given data
Mass of block = 6.3 kg
Mass of bullet = 0.086 kg
Velocity of bullet
= 266

Final velocity of whole system is

Put all the values in above formula we get

262.41

This is the value of speed of wooden block at the instant after the collision.