An engineering student is gathering data on the motion of a model car traveling down a ramp. If energy is conserved, the potential energy of the car at the top of the ramp should equal kinetic energy at the bottom of the ramp. After the first trail, the student calculates that kinetic energy at the bottom of the ramp is less than that the potential energy at the top of the ramp. Which of the following best explains this difference?

Explanation:

When iron reacts with the moisture present in air then an oxide layer tends to develop on the surface of iron. This process is known as rusting of iron.

Chemical formula of rust is . This layer of oxide on the surface of iron is orange-brown in color.

This change is a chemical change as a new compound iron oxide has formed in this process of rusting.

Hence, this orange-brown color on the surface of iron helps us to know that rusting has taken place.