A gun is a heat engine. In particular, it is an internal combustion piston engin

Question

A gun is a heat engine. In particular, it is an internal combustion piston engine that does not operate in a cycle, but comes apart during its adiabatic expansion process. A certain gun consists of 1.55 kg of iron. It fires one 2.40 g bullet at 305 m/s with an energy efficiency of 1.40%. Assume that the body of the gun absorbs all of the energy exhaust and increases uniformly in temperature for a short time before it loses any energy by heat into the environment. Find its temperature increase.
    

Explanation / Answer

The kinetic energy of the bullet:

KE = 1/2 m v^2
= 1/2 * (2.60/1000) * (332)^2 Joules

The heat absorbed by the gun comes from the ratio of the given efficiencies:

Q = KE * (98.9/1.1) Joules

The temp rise of the gun follows from the absorbed heat:

dT = Q/(m*Cp)
= Q / (1.90 * 448) deg C

Should get about 15 C. Crank it out.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.