A student designs a toy car by adding rubber wheels to a box. Attached to the top of the box is a thick paper rectangle. When the paper is aligned with the box (Figure 1), the car covers a long distance when pushed. When the paper is perpendicular to the box (Figure 2), the car covers less distance when given the same push. Why does the toy car cover less distance when the paper is perpendicular to the box?

Consider a one meter long horizontal pipe with a constant 100 cm^2 cross sectional area. water flows rightward into the pipe at x = 0 with flow velocity 02m/sec at every point within the pipe intake area. at x=1, the rightward flow rate is 0.192 m/sec. assume the water is a conserved quantity in the pipe, so there must be a leak (a sink) somewhere in the pipe. 1. compute net volumetric flow of the source if the system to be in equilibrium. 2. now assume the pipe in the problem has no leaks. compute the net volumetric rate of change for the system.