2BM-BP=2(BA-AM)-BP=2BA-2AM-BP=2BA-AM-MP-BP=2BA-AM-BM=2BA-AB=AB=24;
当PB=AM;则:AM=MP=PB=8 AP=16;所以动了16/2=8秒;
(1)当M在B点左侧时:
MN=MB+BN=(AB-AM)+BP/2=AB-AP/2+BP/2=AB-(AP-BP)/2
=AB- AB/2=AB/2=12
当M在B点右侧时:
MN=AN-AM=(AB+BN)-(MN+NP)=AB-MN;
MN=AB-MN;故而MN=AB/2=12;
由此可见: MN长度不变是对的;
(2)显然随着p移动,AM的值逐渐变大,PN的值逐渐变大,AM+PN也会逐渐变大,不会是 定值。
AM=MP,BM=AB-AM
2BM-BP=2(AB-AM)-BP=2AB-2AM-BP=2AB-(AM+MP+BP)=2AB-AB=AB
2. AM=BP=MP,AM+MP+BP=24,AP=2AM=16,t=16/2=8s
3. AM=MP=1/2AP,BN=NP=1/2BP,AB+BP=AP
MN=PM-PN=1/2AP-1/2BP=1/2(AP-BP)=1/2AB
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