Hello there! Once again, I really need some help with a physics problem I have not been able to figure out. Unfortunately, I do not even have a clue how to solve this one and have spent quite a lot time on it. Here is the question: Billy the Kid is throwing an apple with mass 200 grams vertical in to the air. He is shooting with his gun at it and the bullett is hitting the apple at the apple's highest point of its throw. The bullet has a mass of 10 grams and its velocity right before the impact is 300 m/s. Due to the full penetration, the bullet's kinetic energy decreases to only 1/4 of its original value. How great is the energy of deformation during the penetration ? Apparently, my trys ended unsuccessfully and I never got the result of 331,875 J I am not expecting a whole solution, a hint would be great! I really want to figure that out and would be very happy about every help I can get!