A 5.00-g bullet is fired into a 900-g block of wood suspended as a ballistic pendulum. The combined mass swings up to a height of 8.00 cm. What was the kinetic energy of the bullet immediately before the collision

The value is  

Explanation:

From the question we are told that

   The mass  of the bullet is

  The mass  of the wood is  

   The height attained by the combined mass is  

Generally according to the law of energy conservation    

Here is the kinetic energy of the bullet before collision.

and is the  potential  energy of the combined mass of bullet and wood at the height h which is mathematically represented as

So

=>