Question 1: This is a true story -- Back in the day, when I was an undergraduate student, I was walking down a city street with a friend who was talking to me urgently about something very important to him. He walked straight into a parking meter and the spring recoil of the meter knocked him on his butt. After laughing for a long time we realized neither of us had any idea why that had happened. But you do %u2013 so write an explanation of how the human brain allows such concentration on one thing to lead to disaster with another.

Question 2: Suppose you want to pick up a heavy box from a table and you want to keep your back and legs vertical and straight while you pick up the weight. That is, you want to use only your arm muscles to pick it up. After trying a variety of weights, you find you can pick up a greater weight if you start with your arms bent at about 30 degrees than if they are straight. Explain in detail why this is so.