With a more realistic estimation, we assume only 90% of the heat generated is ab

Question

With a more realistic estimation, we assume only 90% of the heat generated is absorbed by a lead bullet. If the lead bullet is initially at room temperature of 20.0°C, what is the minimum speed of the bullet if it just reaches the melting point of 327°C inside the pine wall when it stops? (As we can see in the next section, it will take much more energy to actually melt it.)

vmin =

(As you can see from the pictures, I already attempted the question with an answer of 341.14 m/s, that is wrong. I also tried 399.55 m/s and that is also incorrect.)

Example 20.3Fun Time for a Cowboy Example 20.3 A cowboy fires a silver bullet with a muzzle speed of 210 m/s into the pine wall of a saloon. Assume all the internal energy generated by the impact remains with the bullet. What is the temperature change of the bullet?

Explanation / Answer

By Conservation of Energy:

Heat absorbed by Bullet is equal to change in Kinetic energy

As only 90% of Heat Energy is being absorbed by a Lead Bullet, So

90/100*(mC(Tf-Ti)) = 1/2*m((vmin)2 -0)

vmin = (C(327-20)*2*9/10)1/2

= (234*307*2*9/10)1/2

= 359.59 m/s

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---

---

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