A pendulum on a grandfather clock is supposed to oscillate once every 2.00s but actually oscillates once every 1.99 s how much must you increase its length to correct it's period to 2.00 s?

Aplane flying horizontally at an altitude of 1 mile and a speed of of 500mih passes directly over a radar station. find the rate at which the distance from the plane to the station is increasing when it is 2mi away from the station.