1. The blood flows from the aorta of radius 1.0 cm to the capillaries whose total cross-section is 0.07 m^2. The average speed of the blood flowing in these capillaries is 9.0 x 10^-4 m/s. Calculate the speed of blood flowing through the aorta.

2. A bullet train was speeding on countryside along a straight track at a speed of 100 m/s when the watcher spotted a cow standing along the track. The driver hit the brakes 250 m away from the cow. If the train stopped right before the cow, how long did the brakes engaged?