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.
In the United States, the U.S. dollar determines the value of money. There are three ways to measure the value of the dollar. The first is how much the dollar will buy in foreign currencies. The exchange rate measures that value. Forex traders on the foreign exchange market determine that value. They take into account current supply and demand, as well as their expectations for the future. For this reason, the value of money fluctuates throughout the trading day. The second method is the value of Treasury notes.