Question

十万火急～！！高分悬赏大学英文的物理练习题..

1. A "seconds pendulum" is one that moves through its equilibrium position once each second. (The period of the pendulum is precisely 2.000 s.) The length of a seconds pendulum is 0.9930 m at Tokyo and 0.9942 m at Cambridge, England. What is the ratio of the free-fall accelerations at these two locations?
(g Cambridge / g Tokyo) = _____

2. The position of a particle is given by the expression x = 6.00 cos (2.00πt + π/4), where x is in meters and t is in seconds.
(a) Determine the frequency.
_______ Hz

(b) Determine period of the motion.
________ s

(c) Determine the amplitude of the motion.
________ m

(d) Determine the phase constant.

_______ rad

(e) Determine the position of the particle at t = 0.290 s.

________ m

4. A block of mass M hangs from a rubber cord. The block is supported so that the cord is not stretched. The unstretched length of the cord is L0, and its mass is m, much less than M. The "spring constant" for the cord is k. The block is released and stops momentarily at the lowest point.
(a) Determine the tension in the string when the block is at this lowest point. (Use the following variables as necessary: L_0 for L0, m, M, and g.)
T = ________

(b) What is the length of the cord in this "stretched" position? (Use the following variables as necessary: L_0 for L0, k, m, M, and g.)
L =_______
(c) If the block is held in this lowest position, find the speed of a transverse wave in the cord. (Use the following variables as necessary: L_0 for L0, k, m, M, and g.)
v =________

5. A piano string having a mass per unit length equal to 4.80 10-3 kg/m is under a tension of 1 250 N. Find the speed with which a wave travels on this string.
______m/s

7. A block–spring system vibrating on a frictionless, horizontal surface with an amplitude of 2.0 cm has an energy of 10 J. If the block is replaced by one whose mass is twice the mass of the original block and the amplitude of the motion is again 2.0 cm, what is the energy of the system?
______J

8. A mass–spring system moves with simple harmonic motion along the x axis between turning points at x1 = 19 cm and x2 = 81 cm.
(i) At which position does the particle have the greatest magnitude of momentum?
______

(ii) At which position does the particle have greatest kinetic energy?
______

(iii) At which position does the particle–spring system have the greatest total energy?
______
10. Sinusoidal waves 5.00 cm in amplitude are to be transmitted along a string that has a linear mass density of 4.00 10-2 kg/m. The source can deliver a maximum power of 291 W, and the string is under a tension of 111 N. What is the highest frequency f at which the source can operate?
_____ Hz

13. The distance between two successive peaks of a sinusoidal wave traveling along a string is 2 m. If the frequency of this wave is 4 Hz, what is the speed of the wave?

求高手解~能答多少答多少~在线等答案啊!!!!!好的有加分~

Answer 1

1.gC/gT=LC/LT=0.9942/0.9930=?(自己算吧)
2.
(a) Determine the frequency.
1
Hz

(b) Determine period of the motion.
1
s

(c) Determine the amplitude of the motion.
6 m

(d) Determine the phase constant.
Pi/4

(e) Determine the position of the particle at t = 0.290 s.
把t带入，这个只是计算而已，没技巧。。。
剩下的。。。自己努力吧
楼主在UNSW？
10题，点击master it，试试~
13题，用v=lamda*f不就可以了吗？

Answer 2

楼主是UNSW的吧，这个不就是物理quiz 4的题目吗

Answer 3

NB.....原来大家都是UNSW的啊。。。。。