3. Describe the significance of determining the trajectory and angle of impact of a projectile when trying to solve a crime. 4. Describe the type of evidence that could be recovered from firearms , bullets, and cartridge casings that could help link evidence to a particular firearm.

3. Determining the trajectory and angle of impact of a projectile is crucial in solving a crime as it can provide valuable information about the events that took place. By analyzing the trajectory, investigators can determine the origin of the projectile, the direction it was fired from, and the distance it traveled. This information can help identify the location of the shooter and establish a timeline of events. Additionally, understanding the angle of impact can help determine the position of the victim or object struck by the projectile, providing further evidence to support the investigation.<br /><br />4. Firearms, bullets, and cartridge casings can provide significant evidence in linking evidence to a particular firearm. Ballistic experts can analyze the unique markings left on bullets and cartridge casings by the firearm's barrel and firing pin, respectively. These markings can be compared to those found at the crime scene to identify the specific firearm used. Additionally, gunshot residue analysis can be conducted on the hands or clothing of individuals suspected of firing a weapon, providing further evidence to link them to the firearm. By examining these types of evidence, investigators can establish a connection between the firearm and the crime, aiding in the identification of the perpetrator.