When the average kinetic energy of the molecules goes up (a rise in temperature), the average speed of the molecules increases. And lower average kinetic energy of the molecules means they have lower speed. However, a change in average kinetic energy is not directly proportional to a change in average speed. 1.
An appreciation means an increase in the value of a currency. It means a currency is worth more in terms of foreign currency.
Time Value of Money. The Time Value of Money concept says that a dollar received today is worth more than a dollar received in the future. If you receive money two years from now you have lost two years worth of interest on that money. It is better to get the cash now and earn interest.