A bullet of relatively small mass can cause fatal injury. This is primarily attributed to its:

Correct Option

The correct option is

Large momentum resulting from high velocity.

Explanation

The impact capability of a moving body is determined by its momentum and kinetic energy. Momentum is the product of mass and velocity ($p = m \times v$). According to Newton's Second Law of Motion, the force exerted by an object upon impact is directly proportional to the rate of change of its momentum.

Option Analysis

• Sharp aerodynamic shape.: Incorrect. While a sharp aerodynamic shape reduces air resistance and aids penetration, it is not the primary source of the physical force or energy required to cause extensive damage.
• Large momentum resulting from high velocity.: Correct. Although a bullet has a relatively small mass, it travels at an extremely high velocity. This results in a large momentum ($p = mv$). When the bullet strikes a target, it comes to rest in a very short interval of time. This rapid change in momentum exerts a tremendous force on the target, causing fatal injury.
• High temperature generated by friction.: Incorrect. Friction does generate heat during flight and impact, but the primary mechanism of injury is mechanical trauma caused by the transfer of kinetic energy and momentum, not thermal burns.
• Ability to overcome the inertia of the target.: Incorrect. While the bullet does overcome the inertia of the tissues it penetrates, this is a general description of interaction. The specific physical quantity that quantifies the potential for impact force in this context is the large momentum derived from high velocity.

Key Takeaway: A body with small mass can exert a massive impact force if it possesses very high velocity, as this results in significant momentum (and kinetic energy) that is transferred to the target upon impact.