11. Is it easier to walk to the front or rear of a passenger train when it is stopping? Why?
12. Why does lowering the handles of a wheel-barrow on the instant of striking make it easier to go over a bump?
13. Why should a strong side wind interfere with a game of tennis? How can it be allowed for?
14. On which side of a railroad track at a curve is it the safer to walk while a train is passing? Why?
15. Why does a bullet when fired through a window make a clean round hole in the glass, while a small stone thrown against the window shatters the glass?
16. A tallow candle can be fired through a pine board. Why?
17. In cyclones, straws are frequently found driven a little distance into trees; why are the straws not broken and crushed instead of being driven into the tree unbroken?
18. A bullet weighing one-half oz. is fired from a gun weighing 8 lb. The bullet has a velocity of 1800 ft. per second. Find the velocity of the "kick" or recoil of the gun.
18. When football players run into each other which one is thrown the harder? Why?