A car accelerates at 3ms^-2 along a straight horizontal road. A child of mass 10kg is sitting on a safety seat inside the car. Find the magnitude of the resultant force exerted by the safety seat on the child.
A. 30N
B. 100N
C. 104N
D. 130N
我想要個答案同埋解釋
我想問下 2003 CE Physics MC 第8題
2008-07-18 1:26 am
回答 (2)
2008-07-18 2:23 am
✔ 最佳答案
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When the car accelerates at 3ms^-2 ,the child acclerates at 3ms^-2 as well.The net force acting on the child in the horizontal direction is F=10x3=30.Also,the car exerted a force ,which is the normal reaction(100N),on the child.So the force exerted by the safety seat on the child should be the resultant force of the noraml reaction and the force F,i.e.√30^2+100^2=104N//
2008-07-18 1:46 am
首先有兩個力作用在child上...一是椅背對child的正交力...
二是椅面對child的法向反作用力......
椅背是3*10...椅面是10*10...
再計算合力...30^2十100^2=合力^2...
便可計算到c.........
二是椅面對child的法向反作用力......
椅背是3*10...椅面是10*10...
再計算合力...30^2十100^2=合力^2...
便可計算到c.........
收錄日期: 2021-04-25 23:22:18
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