Final answer:
The subject of this question is Physics, and it involves understanding the motion and interaction of objects in the context of friction, velocity, and energy. The bullet's momentum is transferred to the block, resulting in the block's final velocity being the same as the initial velocity of the bullet. The initial velocity of the block can be found using the principle of conservation of energy.
Step-by-step explanation:
The subject of this question is Physics. The question involves understanding the motion and interaction of objects in the context of friction, velocity, and energy.
Firstly, we can use the principle of conservation of momentum to determine the velocity of the block after the bullet goes through it. Since the bullet is initially at rest and it goes completely through the block, the bullet's momentum is transferred to the block. The momentum before the collision is zero, and this momentum is conserved after the collision. Thus, the block will have a final velocity of 430 m/s, the same as the initial velocity of the bullet.
To find the initial velocity of the block, we can use the principle of conservation of energy. The kinetic energy of the bullet before the collision is equal to the kinetic energy of the block and bullet after the collision. Using the formula for kinetic energy, we can calculate the initial velocity of the block as 190 m/s.