15. A bullet of mass 0.5 kg is moving horizontally with a speed of 50 m/s when it hits a block of mass 3 kg that is at rest on a horizontal surface with a coefficient of friction of 0.2. After the collision the bullet becomes embedded in the block. a. What is the net momentum of the bullet-block system before the collision? b. Find the total energy of the bullet-block system before the collision? C. What is the speed of the bullet-block system after the collision? d. *Find the total energy of the bullet-block system after the collision?