使用托盘天平测物体质量。将托盘天平放在水平桌面上，游码放在天平标尺的零刻线处，调节天平横梁的平衡。在调节天平横梁平衡时，如果指针所处的位置如图所示，为使天平横梁在水平位置平衡，应将天平右端的平衡螺母向________移动。把金属块放在调节好的天平的左盘中，当天平平衡时，右盘中的砝码以及游码在标尺上的位置如图所示，则金属块的质量是________g。（2分）
右，174
中指针偏向分度盘左侧，因此要向右移动平衡螺母，直到指针指在分度盘的中间；天平平衡时，左盘物体的质量等于右盘砝码的质量和游码质量的和，即m=100g+50g+20g+4g=174g．
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| Tired and exhausted, I come back home from work. I found the front door was 1 open and I felt a little scared. Did I carelessly forget to lock it after I left? I looked around 2 to see what could be 3 . Why would someone come into my home only to 4 with nothing? After searching every inch, I realized that everything was 5 I had left it. No 6 cushions, broken lamps, or 7 emptied out on the carpet. Feeling much 8 , I looked out my oversized window of my dinning room at Ms. Sullivan's house. Jimmy, the little boy next door was visiting her. Jimmy cared a lot about Ms. Sullivan and was very concerned with her health after she became ill. She used to 9 Jimmy when he was just a baby. Forgetting about the 10 with my front door, I decided to walk over to Ms. Sullivan's house to see how she was 11 . With a warm hello, she invited me into her home. I noticed twelve beautiful roses delicately presented on the table next to her bed. They looked exactly like the 12 on my dinning room table in front of my oversized window. With a pleasant smile, she told me Jimmy brought them to her as a "get-well gift". Suddenly Jimmy 13 out of his seat in an instant and said that he had to go home for a while to do some homework but he promised to be back to 14 up on Ms. Sullivan. Talking for a while, Ms. Sullivan began to get very tired so I gave her my phone number in case she 15 needed help, and left her home. I thought about how 16 it was for little Jimmy to be so concerned for Ms. Sullivan. I got home, laughing at how 17 I was that morning about what had happened over 18 . I walked passed the dinning room and noticed my roses 19 in the vase were missing. Without a second 20 , I glanced out the window at Ms. Sullivan's house and with a smile on my face I turned off the light in the room and went to sleep. The next morning my door bell rang. I opened the door and Jimmy was there... | ||||
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