Answer:8 m/s
Explanation:
Given


kinetic Energy of 
initially
is at rest and let say
is moving with velocity u
kinetic Energy of 


In Completely inelastic collision both mass stick together and move with common velocity
Suppose v is the common velocity


therefore Final velocity with which both blocks moves is 1 m/s
-- Class I lever
The fulcrum is between the effort and the load.
The Mechanical Advantage can be anything, more or less than 1 .
Example: a see-saw
-- Class II lever
The load is between the fulcrum and the effort.
The Mechanical Advantage is always greater than 1 .
Example: a nut-cracker, a garlic press
-- Class III lever
The effort is between the fulcrum and the load.
The Mechanical Advantage is always less than 1 .
I can't think of an example right now.