Halliday, Resnick & Walker — Motion in Two and Three Dimensions: Problem 124

Disappearing bicyclist. Figure 4.40 is an overhead view of your car (width $C = 1.50 \text{ m}$) and a large truck (width $T = 1.50 \text{ m}$ and length $L = 6.00 \text{ m}$). Both are stopped for a red traffic light waiting to make a left-hand turn and are centered in a traffic lane. You are sitting at distance $d = 2.00 \text{ m}$ behind the front of your car next to the left-hand window. Your street has two lanes in each direction; the perpendicular street has one lane in each direction; each lane has width $w = 3.00 \text{ m}$. A bicyclist moves at a speed of $5.00 \text{ m/s}$ toward the intersection along the middle of the curb lane of the opposing traffic. Sight line 1 is your view just as the bicyclist disappears behind the truck. Sight line 2 is your view just as the bicyclist reappears. For how long does the bicyclist disappear from your view? This is a common dangerous situation for bicyclists, motorcyclists, skateboarders, inline skaters, and drivers of scooters and short cars.