我還有一個物理問題';
2 particles, each with mass m=0.85kg, r fastened to each other, and to a rotation axis at 0, by two thin rods, each with length d=5.6cm and mass M=1.2kg . The combination rotates around the rotation axis with angular speed w=0.30 rad/s. measure about O, what are the combination's (a.) rotational inertia and (b.) kinetic energy?
這題的解答是不是因該先算total mass ...然後在用公式I = mr^2 得到 inertia..然後用KE = (1/2) mv^2 得到kinetic energy?
1題物理題發問
2009-06-20 1:54 am
回答 (2)
2009-06-20 3:08 am
✔ 最佳答案
a. For the rod, its rotational inertia about O = 1/3 Md2
= 1/3 (1.2)(0.056)2
= 1.2544 X 10-3 kgm2
For the particle, its rotational inertia about O
= md2
= (0.85)(0.056)2
= 2.6656 X 10-3 kgm2
So, the total rotational inertia, I
= 2 X (2.6656 X 10-3 + 1.2544 X 10-3)
= 7.84 X 10-3 kgm2
b. The kinetic energy of the system
= 1/2 Iw2
= 1/2 (7.84 X 10-3)(0.30)2
= 3.528 X 10-4 J
參考: Physics king
2009-06-22 9:13 pm
我看過答案..好像不是呢.....
1.) 0.023 kgm2
2.) 11mj
1.) 0.023 kgm2
2.) 11mj
收錄日期: 2021-04-19 14:56:53
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090619000015KK07441