Answer to Question #276396 in Physics for Rakibul

Question

(a) What is an example of the first law of thermodynamics? 5.0-g bullet traveling at a

speed of 300 m/s enters a tree and exits the other side with a speed of 150 m/s.

Where did the bullet’s lost kinetic energy go, and how much energy was

transferred?

(b) What is the application of thermodynamics in engineering studies?

Answer 1

The first law of thermodynamics states that the total energy of a system remains constant, even if it is converted from one form to another. For example, kinetic energy—the energy that an object possesses when it moves—is converted to heat energy when a driver presses the brakes on the car to slow it down.

The the bullet’s lost kinetic energy go into heat.

$$K=0.5(0.005)(300^2-150^2)=169\ J$$

Thermodynamics has very wide applications as basis of thermal engineering. Almost all process and engineering industries, agriculture, transport, commercial and domestic activities use thermal engineering. But energy technology and power sector are fully dependent on the laws of thermodynamics.