Move the chemistry book down again so it's surface touches the physics book. Quickly move the chemistry book back and forth. What's different when motion is faster?

The temperature of the physics book increases as the chemistry book slides across it.

Explanation:

from plato

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.