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.
1 China has allowed the value of its currency to fall by nearly 2% against the U.S. dollar. 2  Some say move is aimed at boosting China's struggling economy. 3  Others say China is allowing market forces a freer hand.