Two bank robbers flee a bank after a robbery. Once they exit the building, one runs north and another runs east. The policeman in the vicinity is walking 10 feet northeast of the bank at a rate of 2ft/sec south. Convict 1 runs north at a rate of 3ft/sec while holding the money and Convict 2 runs east at 5ft/sec. What are the rates of change and distances between the policeman and the convicts at a) 3 seconds b) 4 seconds?