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1987年高考物理题第二大题(选择题)第10小题是一道颇有新意的好试题,值得进行探讨。原题:图中M、N是两个共轴圆筒的横截面,外筒半径为R,内筒半径比R小很多,可以忽略不计,筒的两端是封闭的,两筒之间抽成真空。两筒以相同的角速度ω绕其中心轴线(图中垂直于纸面)做匀速转动。设从M筒内部可以通过窄缝s(与M筒的轴线平行)不断地向外射出两种不同速率v_1和v_2的微粒,从s处射出时的初速度的方向都是沿筒的半径方向,微粒到这N筒后就附着在N筒上。如果R、v_1和v_2都不变,而ω取某一合适的值,则 A.有可能使微粒落在N筒上的位置都在a处一条与S缝平行的窄条上。
The second topic of the 1987 college entrance examination physics question (multiple-choice questions) is a good new test question that is worthy of discussion. The original title: M and N in the figure are the cross-sections of two coaxial cylinders. The radius of the outer cylinder is R. The radius of the inner cylinder is much smaller than R and can be ignored. The ends of the cylinder are closed, and the two cylinders are pumped. Become a vacuum. The two cylinders rotate at a uniform angular velocity ω around their central axis (perpendicular to the paper surface). From the inside of the M cylinder, two slits s (parallel to the axis of the cylinder M) can continuously eject two particles of different velocity v_1 and v_2, and the direction of the initial velocity emitted from s is along the radius of the cylinder. After the particles reach the N-tube, they are attached to the N-tube. If R, v_1, and v_2 both do not change, and ω takes a suitable value, then A. may cause the particles to land on the N-barrel at a location on a narrow strip parallel to the S-slit.