A truck is brought to a stop when its brakes are applied. What type of energy conversion takes place?

This option is incorrect because elastic potential energy refers to energy stored in objects that can be stretched or compressed, such as springs. In the context of a truck stopping, no elastic potential energy is involved, nor is there a conversion to chemical potential energy, which pertains to energy stored in chemical bonds.

This choice is incorrect as it describes a scenario where an object's height is converted into motion, such as a falling object gaining speed. However, in this case, the truck is not gaining kinetic energy; it is losing it as it comes to a stop, which does not fit the scenario presented.

This option is also incorrect. Chemical potential energy relates to energy stored in the chemical bonds of fuel or other substances, while gravitational potential energy is related to an object's height in a gravitational field. The stopping of a truck does not involve these conversions; instead, it focuses on the loss of kinetic energy.