Entropy change of a bullet hitting water

[KaiserBrandon]

Homework Statement

Calculate the change in entropy when a lead bullet of mass 10 grams traveling at 500 m/s hits a very large volume of water. Assume that the bullet was initially at 150 degrees Celsius and the water was at 25 degrees Celsius.

Homework Equations

$$K=\frac{1}{2}\,{{\it mv}}^{2}$$
$$\Delta S={\frac {\delta Q}{T}}$$

The Attempt at a Solution

So I calculated the kinetic energy of the bullet to be 1250J. If the bullet is stopped by the water, that 1250J becomes thermal energy. Now this is where I'm stuck. I'm not exactly sure how to determine how much of that thermal energy is absorbed by the bullet, and how much by the water.

 

[Mapes]

I'm not exactly sure how to determine how much of that thermal energy is absorbed by the bullet, and how much by the water.

In the end, it's all absorbed by the water, and the bullet also ends up at 25 degrees C. And since entropy is a state function, you don't need to worry about intermediate temperatures. Does this help?

 

[KaiserBrandon]

ok, I wasn't sure if the system was allowed to reach equilibrium or not.