This document is an answer to the letter from State Plan of Ukrainian Soviet Socialistic Republic to Academy of Sciences of USSR “About Rationality to Construct Cyclotron in UIPhT” (22 Feb 1940). The answer of academician Petr Kapitsa to this letter was very critical. Kapitsa wrote that UIPhT “during the last several years built a number of research installation but did not finish them. However it started to build new installations. Such activities of UIPhT can’t be considered as normal”. So Petr Kapitsa discouraged building a cyclotron in UIPhT, and this was one of the reasons why this institute did not become the leading nuclear center in USSR.