A 5.00-g bullet is fired horizontally into a 1.20-kg wooden block resting on a horizontal surface. The coefficient of kinetic friction between block and surface is 0.20. The bullet remains embedded in the block, which is observed to slide 0.230 m along the surface before stopping. What was the initial speed of the bullet?

The initial velocity of the bullet is  

Explanation:

From the question we are told that

          The mass of the bullet is  

           The mass of the wooden block

          The coefficient of kinetic friction

          The  distance traveled by block and bullet

let   denote the force on the bullet in the block and this mathematically denoted as

Where m is the mass of both bullet and block

  Substituting values

Generally workdone is mathematically represented as

the  work in this cause in the kinetic energy used to move the block and bullet

                 i.e      

Where   is the final speed of the block and bullet

           Therefore  

making the subject

Here m is the mass of both bullet and block

Now substituting values

From the law of conservation of momentum this collision can be mathematically represented as

Now from the question    this because the block was at rest

                          Therefore

    Substituting values

f=ma newton

f=100x2.5=250n