Classical physical selection Two short and thick pipes are connected on both sides of the container. They are bent upward to make two water sprayers. However, one of the nozzles shrinks into a nozzle, and the other nozzle is completely open A. the water flow from the big pipe is higher than that from the small pipe C both of the water jet is as high, C can't judge, please explain!

Classical physical selection Two short and thick pipes are connected on both sides of the container. They are bent upward to make two water sprayers. However, one of the nozzles shrinks into a nozzle, and the other nozzle is completely open A. the water flow from the big pipe is higher than that from the small pipe C both of the water jet is as high, C can't judge, please explain!

Because a nozzle shrinks, so the air flow speed becomes faster, so the pressure is smaller, so the spray is higher, so choose B

A and B pull the same spring dynamometer in the opposite horizontal direction, and the dynamometer remains stationary. If the indication is 80 n, the pull of each person is ()
A. 40NB. 80NC. 160ND. 20N

Both ends of the spring dynamometer are subject to horizontal tension. The two tensions are in a straight line and opposite directions, which is a pair of balanced forces. Therefore, the tension on the hook end of the spring dynamometer should be subject to the indication of the spring dynamometer, so the tension is 80N

Inspired by the flying of birds in the air, people invented the aircraft. The upward lifting force obtained by the bird flapping its wings can be expressed as F = ksv2, where s is the wing area, V is the flight speed of the bird, and K is the proportional coefficient. The minimum flight speed of a swallow with a mass of 100g and a wing area of S0 is 10m / s The lift force of a plane with a mass of 3600kg has the same law. The wing area of the plane is 1000 times that of the swallow's wing area. What is the takeoff speed of the plane?

For flying birds, the minimum flight speed is set as V1 & nbsp; & nbsp; & nbsp; Mg = KS & nbsp; 0v21 ① For an aircraft, let the minimum take-off speed be V2 & nbsp; & nbsp; Mg = ksv22 & nbsp ② By comparing the two formulas, mm = s0v21sv22 ③ Substituting the data, V2 = 60m / s ④...

What are the physical meanings of N, l, m and MS in quantum mechanics and Bohr quantum theory

In Bohr's quantum theory, there are only N, not the last three, so it is only a transition theory. These four quantum numbers will appear when quantum mechanics deduces the motion of electrons in atoms. N is the main quantum number, which usually has the greatest influence on the energy of electrons. It mainly means the distance between the electron and the "average distance" of the nucleus, the farther