## 2070.83 – Bowling Uphill

After the earthquake, Jojo found that the bowling alley slanted upwards. The slant was gentle enough so that the pins didn't fall over but he had to roll the ball upwards towards them. When he rolled the ball it went with a velocity of $30 - 8t$ feet per second, where $t$ was 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 in words? (e) How fast would Jojo roll a ball in a flat lane?

## Solution

(a) 22 ft/sec, (b) 6 ft/sec, (c) -2 ft/sec, (d) after 3 seconds the ball is rolling backwards, (e) 30 ft/sec.