Given the following information regarding a typical cartridge of 9mm ammunition: $$\begin{array} { | r | l | l | }
\hline 1 \text { gram } & 15.43 & \text { grains } \
\hline \text { Propellant energy } & 4545 & \mathrm {~J} / \mathrm { g } \
\hline \text { Mass of propellant } & 5.7 & \text { grains } \
\hline \text { Efficiency } & 59 \% & \
\hline \text { Bullet weight } & 115 & \text { grains } \
\hline
\end{array}$$ Calculate the mass of the bullet in grams

Question

Given the following information regarding a typical cartridge of 9mm ammunition: $$\begin{array} { | r | l | l | } 
\hline 1 \text { gram } & 15.43 & \text { grains } \
\hline \text { Propellant energy } & 4545 & \mathrm {~J} / \mathrm { g } \
\hline \text { Mass of propellant } & 5.7 & \text { grains } \
\hline \text { Efficiency } & 59 \% & \
\hline \text { Bullet weight } & 115 & \text { grains } \
\hline
\end{array}$$ Calculate the mass of the bullet in grams

Quizplus · Accepted Answer

The given information is useful for calculating the mass of the bullet in grams using the following formula:
Propellant energy = (1/2) x Mass of bullet x Velocity^2 x Efficiency
We are not given the velocity of the bullet, but we can assume it is a typical velocity for a 9mm bullet, which is around 350 m/s. Substituting the given values:
4545 J/g = (1/2) x Mass of bullet x (350 m/s)^2 x 0.59
Solving for Mass of bullet, we get:
Mass of bullet = 7.48 g
Converting from grams to grains, we get:
Mass of bullet = 115 grains
Therefore, the correct answer is C) 7.5.

Given the Following Information Regarding a Typical Cartridge of 9mm