After the earthquake, Junior found that the bowling alley slanted upwards, so that he had to roll the ball upward toward the pins. The slant was gentle enough so that the pins would not fall over, but just barely. He found that when he rolled the ball it went with a velocity of 12 – 4t feet per second (where t is the number of elapsed seconds.) (a) How fast was the ball going after 1 second? (b) How fast was the ball going after 3 seconds? (c) How fast was it going after 4 seconds? (d) What does this mean? (e) How fast does Junior roll the ball on a flat lane?

(a) 8 ft/sec, (b) 0 ft/sec, (c) -4 ft/sec, (d) It’s rolling backwards, (e) 12 ft/sec when flat.