Asection of railroad tracks through southern arizona are laid during the winter when the average temperature is 10 celsius(50fahrenheit). these tracks are made of 1025 steel and make use of expansion joints with gaps that are 4.6 mm (0.18in) wide. there are 16 km (9.9 miles) of track and each rail has a standard length of 11.9 m (39 ft). what is the hottest temperature than can be tolerated on this stretch of railroad without introducing thermal stresses?

What are the similarities of physical and chemical change ?

The characteristics of two different types of reactions are shown below: reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of an element. which statement is true about the atoms of the elements that participate in the two reactions? their identity changes in both reaction a and reaction b. their identity changes in reaction a but not in reaction b. their identity changes in reaction b but not in reaction a. their identity remains the same in both reaction a and reaction b.

Which is an example of a reversible physical change?