[理工] [動力]-成大97-機械-考題
http://tr.im/PslV
97成大機械第四題
解答一
θ=tan-1(3/4)=36.87
4*sin36.87*sin36.87=1.44
ΣMo=(ΣMo)eff
1.44*100*9.81=100*4α*1.44+1/12*100*8^2*α
α=1.27 rad/s2
ΣMG=(ΣMG)eff
T*(3/5)*4=1/12*100*8^2*1.27
T=282
解答2
ΣMG=(ΣMG)eff
T*(3/5)*4=1/12*100*8^2α
T=222.22α
ΣFn=ma
T-(4/5)*100*9.81=-100*(4/5)*(4α)
T=784.8-320α
α=1.447
T=321
在不同參考書看到的解法不一樣,乍看之下,好像都是對的,因為兩者的誤差有點大,感
覺很奇怪。煩請指點一下,請問那一份解答才是正確的?
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