4. The last slide on lecture 2B shows a picture with a display of the 'approximate speed' and approximate distance' for an object falling with negligible air resistance. For this approximation we assume that the acceleration of gravity is about 10 m/s/s. Extend the picture and give the values for an object falling from a higher tower after 6 seconds and 7 seconds. The speed is fairly easy to calculate. The distance is a little trickier. You might guess that it is the speed you calculate multiplied by the time. But since it just reaches that speed right at the end of the time interval (and has been moving more slowly before that) this overestimates the distance. It turns out the real distance is just one half of this first guess.