Transforming kinetic energy into thermal energy

In summary, the problem involves two cars colliding head on at a speed of 80 km/h and all of their kinetic energy being transformed into thermal energy. Assuming the specific heat of iron, the temperature increase of each car can be calculated using the equation ΔT=v^2/2c. After converting the units of velocity from km/h to m/s and using the specific heat of iron, the temperature increase is calculated to be 0.55 C.
  • #1
nlingraham
16
0

Homework Statement



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

Homework Equations



K=1/2mv2

Q=mcΔT

1/2mv2=mcΔT

∴ ΔT=v2/2c

The Attempt at a Solution



I worked it out using 80 km/h for v and 449 J/kg * K for c and got 7.13 K. My question is if this is right, and if it is can someone explain to me how the units cancel out to give just K?
 
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  • #2
Express J in terms of kg, m and s. What is the dimension of c then?
 
  • #3
Ok, I got it. J=kg*m2/s2. So that meant I had to convert 80 km/h to 22.22 m/s for everything to cancel out. I ended up getting .55 C. Thank you for your help.
 

1. How does kinetic energy transform into thermal energy?

When an object is in motion, it possesses kinetic energy. When it collides with another object or surface, the kinetic energy is transferred to the particles of the object or surface, causing them to vibrate faster and increase their thermal energy. As more collisions occur, the thermal energy of the object or surface also increases.

2. Can all forms of kinetic energy be transformed into thermal energy?

Yes, all forms of kinetic energy, such as mechanical, electrical, and thermal, can be transformed into thermal energy through collisions and friction. However, the amount of thermal energy produced may vary depending on the type of kinetic energy and the materials involved in the collision.

3. What factors affect the transformation of kinetic energy into thermal energy?

The transformation of kinetic energy into thermal energy can be affected by factors such as the speed and mass of the moving object, the type of material it collides with, and the duration of the collision. Higher speeds and heavier masses typically result in more thermal energy being produced.

4. How is thermal energy used in everyday life?

Thermal energy is used in many everyday activities, such as cooking, heating homes and buildings, and generating electricity. It is also used in various industrial processes, such as melting metals and powering engines.

5. Is it possible to reverse the transformation of kinetic energy into thermal energy?

Yes, it is possible to reverse the transformation of kinetic energy into thermal energy. This can be achieved through processes such as energy conversion and energy storage, where thermal energy is converted back into another form of energy, such as mechanical or electrical energy.

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