初二物理（Physics in junior middle school）.docVIP

初二物理（Physics in junior middle school） The second day physics.Txt, if there is afterlife, to be a tree, standing eternal, no sad gesture. Half in the soil, quiet, half in the wind flying, half fall cool, half bathed in sunshine, very silent, very proud, never rely on never looking for. I. multiple-choice questions: (4. 8=32) 1. a lifter holds a barbell in the air for 3 seconds, and the following forces are correct in 3 seconds A. the balance between the gravity of the athlete and the ground is equal to his support B. the gravity of a barbell is balanced against the pressure on which the athlete is exposed C. an athletes balance between the force of a barbell and the gravity of a barbell D. the pressure on the athlete and the ground support him is a counterweight 2. the following is true () A.s law of inertia, that is, Newtons first law, is derived directly from Newtons experiments The balance nut on the B. balance shall act as a regulating beam in the course of measurement A C. can only measure the volume of D. liquid with the spring balance can be measured by the buoyancy of small stones 3. a, B, C and d a four volume, the same shape and different material of the ball, put them into the water to rest as shown in Figure 1, which is the smallest (by force) A. a, B., B, C., C, D., Ding 4., an egg submerged in a glass of water, add what is to the water, stirring can make the egg floating up, and finally reached the surface of the water, in the process of rising eggs, it is subject to changes in buoyancy A. alcohol, B., salt, C., cooking oil, D., salt, unchanged 5. using a glass tube with a length of about 1m to do the Tori demolition experiment. The following is the influence of the vertical height of the mercury column in the pipe A. glass tube thickness B. glass tube tilt The height of the C. experiment D. the depth of glass tubes inserted into mercury 6. as shown in Fig. 2, there is air in the container, and there is a small ball at the bottom. The piston can move up