问题 填空题

物理实验小组利用如图所示装置测量物体平抛运动的初速度.他们经多次实验和计算后发现:在地面上沿抛出的速度方向水平放置一把刻度尺,让悬挂在抛出点处的重锤线的投影落在刻度尺的零刻度线上,则利用小球在刻度尺上的落点位置,就可直观地得到小球做平抛运动的初速度.如图四位同学在刻度尺旁边分别制作了速度标尺(图中P点为重锤所指位置),可能正确的是:______

答案

竖直方向自由落体运动,所以小球落地所用的时间是相同的;水平方向匀速直线运动,位移与初速度的关系是:x=v0t,t一定所以x与v0成正比.故选A

单项选择题

The physicians in a hospital form the core of the medical staff. But they couldn’t provide effective medical care to their patients without the help of numerous other medical employees. From the viewpoint of the patients, the nursing staff is particularly important. Nurses are usually in close contact with patients as long as they are in the hospital.

A nurse does not study for as many years as a doctor. However, each must be equally dedicated. Caring tot sick persons requires a great deal of patience and concern. Most nurses work long days, and they often must work at odd hours or during the night.

Under the supervision of the head nurse, the nursing staff must provide nursing services on 24-hour basis and attend to patients’ needs. This responsibility continues around the clock, and so nurses must work in shifts. A shift is a period of duty, usually eight in length. The nurses on the ward rotate their shifts. All of them work out of a central area on the ward called the nurses’ station.

A nurse must always be alert. She can never afford to be careless. This is true in all nursing situation, but it is especially true in the intensive care unit. Patients under intensive care duty have one of the most demanding jobs in the hospital.

Serving as a nurse can be a very. rewarding job. But it is not an easy one. Not every person is suited to become a nurse. Only very dedicated people have chosen nursing as a profession.

The nursing staff ()

A.are central to the medical staff

B.play an important role in caring for patients

C.can work effectively without physicians

D.are always in close contact with the patients

单项选择题