Two cars collide, find temperature change

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Homework Help Overview

The problem involves a collision between two cars, each traveling at 80 km/hr, and the transformation of their kinetic energy into thermal energy. The goal is to determine the temperature increase of each car, assuming they have the specific heat of iron.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to calculate the kinetic energy and relate it to the thermal energy using specific heat, but expresses uncertainty about their calculations and results.
  • Some participants question the necessity of unit conversion and the interpretation of temperature change versus absolute temperature.
  • Others suggest that the calculated temperature change may still be incorrect, indicating further issues in the approach.

Discussion Status

The discussion is ongoing, with participants exploring different aspects of the calculations and questioning the assumptions made. There is no clear consensus on the correct approach or answer, and the original poster is seeking further assistance.

Contextual Notes

The original poster has expressed confusion regarding their calculations and the correctness of their results, indicating a need for clarification on the concepts involved.

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Homework Statement



Two cars collide head on while each is traveling at 80 km/hr. Suppose all their kinetic energy is transformed into the thermal energy of the wrecks. What is the temperature increase of each car? (Assume each car's specific heat is that of iron)

Homework Equations



K = .5mv^2
Q = cm(delta T)
iron specific heat = .449 J/(g*K)

The Attempt at a Solution



K = 2(.5m(22.2)^2) = 492.8m

(converted 80 km/hr to m/s)

Q = 492.8m = (.449)(2m)T
T = 548.8 K
= 275.6 C

Which is the wrong answer. I don't know what i am doing wrong. Can someone please help me. Thanks
 
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Well, for one, there is no reason to convert your units. You calculated a [tex]\Delta T[/tex], not a temperature, and [tex]\Delta °C = \Delta K[/tex]. Is the correct answer 549.9 K?
 
Oh yeah, I see what your saying. However 549 is still the wrong answer, so i must be doing something else wrong too.
 
Can anyone help me? I am really stuck...
 

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