Explanation of physical phenomena in life

Explanation of physical phenomena in life

(1) Wearing glasses, from cold outdoor to warm indoor, glasses will be covered with white fog, which is the phenomenon of gas liquefaction
(2) When the water boils, the lid will be lifted. It is the gas that does the work on the lid
(3) Sitting in a fast car, when you turn, you will feel outward swing, which is centrifugal phenomenon
(4) The corner of long-term piling coal will turn black, which is the diffusion phenomenon of solid molecules
(5) Drilling wood can make fire, which is to do work to change internal energy
(6) You will feel warm when you lean on the heater. It's heat transfer
(7) Nail scissors, scissors, tweezers work principle, is the lever
(8) There is weightlessness in a pirate ship
(9) Incandescent lamp permanent, bulb wall will have a layer of black, is the sublimation of tungsten

The water flowing from the tap of the water pipe. Under the condition that the water does not disperse, the more it flows down. Is the water thicker or thinner? Please explain this phenomenon

A: the finer the water flow is; after the water flows out from the tap, due to the action of gravity, the water accelerates to flow downward, and the flow velocity becomes larger and larger. Because the pressure of the place where the fluid flow velocity is larger is smaller, the pressure of the water flow becomes smaller, and the flow rate of the water remains unchanged (the volume of water in unit time remains unchanged). When the flow velocity is faster, the water column is flattened and elongated under the action of atmospheric pressure, and the natural water flows The column gets thinner and thinner

Someone is riding a bicycle on a straight road. The solid line in the right picture records the V-T image of the beginning period of the bicycle. In order to simplify the calculation, a student uses the dotted line for approximation
A. At T1, the acceleration reflected by the dotted line is larger than the actual one. B. during 0-t1, the average velocity calculated by the dotted line is larger than the actual one. C. during T1-T2, the average velocity calculated by the dotted line is larger than the actual one. D. during T3-T4, the dotted line reflects the uniform motion

A. At T1, if the slope of the dotted line is less than that of the tangent line of the solid line, then the acceleration reflected by the dotted line is less than the actual acceleration. Therefore, a is wrong. B. if the area enclosed by the dotted line and the time axis is greater than that enclosed by the solid line and the time axis from 0 to T1, then the average velocity calculated by the dotted line is greater than the actual one The average speed calculated by the dotted line is smaller than the actual one. Therefore, C is wrong. D. in T3-T4, the dotted line is parallel to the time axis, reflecting the uniform motion. Therefore, D is correct. Therefore, BD is selected