Because dark line spectra result from passing white light through ionized gasses and plasmas, which is what the atmosphere of stars are made of. These frequencies are scattered by the star's atmosphere as it leaves the surface (photosphere) of the star, and don't make it to earth.
The extrapolated temperature is used to define the maximum temperature of the mixture relatively than the highest recorded temperature in which the conclusion will effect in a higher specific heat value. Heat is bound to escape from whatever apparatus is using, therefore it is needed to account for the loss of the heat that does not go into increasing the temperature of the mixture.
<u>Answer</u>
To increase friction for a better grip.
<u>Answer</u>
Most human beings do sweat hands especially on the palm. When this happens the person will not have a good grip of heavy objects because they will slide/slip from the hand.
<em>By applying the powder, you are trying to make the hand dry hence increasing the friction for a better grip. </em>
If the gymnast doesn't do this the parallel bars may slip from the hands and injure himself or herself.
