I have problems understanding WHEN mechanical work will be converted to heat . If a body moves , will there always be a rise in temperature , even if negligible ? If not , then read this Problem I recently came across , with the solution too : " From what height must a mass of ice be dropped so that the heat generated completely melts the ice block ? " Now , if the ice is not encountering any obstruction . Does that mean , if the ice was dropped from a height above the minimum height , the ice would have melted some distance above , WITHOUT ENCOUNTERING AN OBSTRUCTION ? Now if that is true , it suggests all bodies when set to motion have a rise in temperature .This contradicts my common sense. Please enlighten.