I'm having trouble understanding this word problem. A construction worker drops a bolt while woring on a high-rise building 320m above the ground. After t seconds, the bolt has fallen a distance of s metres, where s(t) = 320-5t^2, o < t < 8 a. Find the average velocity during the first, third and eighth seconds. I have to use f(x + h) - f(x)/h I got 5(t +h) The answer is 5m/s for the first one. How do I get the rest of them (third and eighth second)?