Question 12(Multiple Choice Worth 1 points) (05.07 HC)

Which statement is true about space technology?

I-t has made air travel safer because photopolarimeters are used to send signals while flying at high altitudes.
-It has made road vehicles safer because magnetometers are used to detect particles found in radiation emitted during combustion of fuel.
- It has impacted air quality because magnetometers are used to detect particles found in radiation emitted during combustion of fuel.
- It has impacted medical science because the infrared thermometers used on Earth were originally designed to measure the temperature on Mars.

c-14 is carbon-14, or radiocarbon.   it is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.