力F1作用在物体上产生的加速度a1=3m/s2，力F2作用在该物体上产生的加速度a2=4m/s2，则F1、F2同时作用在该物体上，产生的加速度大小不可能为（ ）
A．7m/s2
B．5m/s2
C．1m/s2
D．8m/s2
答案：D
题目分析：力
作用在物体上产生的加速度
，力
作用在该物体上产生的加速度
，因为加速度是矢量，则合加速度
．两个力作用在该物体上产生的加速度，可以看成每个力产生的加速度的合加速度．故D正确，A、B、C错误．
点评：解决本题的关键知道两个力作用在该物体上产生的加速度，可以看成每个力产生的加速度的合加速度．
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| One evening, Peter went home and said to his wife, "You have been a very good wife. You 1 in the home. You have 2 me some very good meals. You have looked after 3 very well. Today is your birthday and I bought you a 4 !" "Oh, thank you," said his wife, "This is a piece of good 5 . What have you bought for me?" "I've bought you a watch," said Peter. He took it out for his wife to 6 but he dropped it. He began to 7 it on the floor, but it was 8 inside their little house and he could not see anything. He went 9 and began to look for the watch in the street. l0 , a friend came along and asked him what was wrong with him. Peter told that to him. The friend smiled and said, "You lost it in your house. Why are you looking for it in the street?" "It is very dark inside the house. I cant see very well." | ||||
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