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.
When the U.S. dollar depreciates relative to a foreign currency, the exchange rate between the two currencies rises. The increased exchange rate means itâs more expensive for a domestic business to convert U.S. dollars to a foreign currency and cheaper for a foreign business to convert its currency to U.S. dollars.