Question

11. A simple pendulum undergoes small-angle oscillations. Which of the following pairs (mass, string length) will oscillate with a period greater than 2.2 seconds?
a) (0.50 kg, 1.0 m)
b) (0.40 kg, 0.80 m)

c) (1.0 kg, 0.50 m)

d) (0.80 kg, 0.40 m)
e) none of the above answers are correct

(numbers 15-17) An ideal horizontal spring-mass system begins oscillation with the mass at x=0 (the spring is relaxed) and moving in the -x direction at 6.00 m/s. The spring has constant 1200 N/m and the mass is 5.00 kg.

15. What is the period of oscillation?

a) 0.706 s
b) 0.606 s
c) 0.506 s

d) 0.406 s

e) 0.306 s

16. What is the amplitude of the motion. a) 0.187 m
b) 0.287 m
c) 0.387 m

d) 0.487 m

e) 0.587 m

17. What is the position of the mass at 0.220 seconds?

a) 0.122 m
b) 0.102 m
c) 0.082 m

d) 0.062 m

e) 0.042 m

(numbers 18-19) Two fire trucks are at rest and their sirens each emit a single frequency. You stand at rest in the middle of the trucks and observe a beat frequency of 12.0 Hz. You experimentally determine that running toward truck 1 (away from truck 2) at 8.50 m/s causes the beat frequency to become zero. The speed of sound is 340 m/s.

18. What is the frequency emitted by truck 1? a) 117 Hz
b) 156 Hz
c) 195 Hz

d) 234 Hz

e) 273 Hz

19. What is the beat frequency if you run toward truck 2 (away from truck 1) at 8.50 m/s? a) 28 Hz
b) 24 Hz
c) 20 Hz

d) 16 Hz

e) 12 Hz

(numbers 20-21) Two speakers emit the same pure tone (sound of a single frequency) and are in phase.

20. An observer begins at the center point between the speakers and slowly moves toward one of the speakers. The second very quiet spot encountered (completely destructive interference) is 2.25 m from the center. What is the wavelength of the sound?
a) 1.0 m

b) 1.5 m

c) 2.0 m

d) 2.5 m
e) 3.0 m

21. If the distance between the speakers is 5.5 m, what is the shortest distance from either speaker where a loud spot (completely constructive interference) is found?
a) 0.75 m
b) 1.25 m

c) 1.75 m

d) 2.25 m

e) 2.75 m

Answer 1

Solution:

Answers :

11)e

15 ) d

16) c

17) b

The time period of the simple pendulum = T = 2 L/g = 2.00  L .It is independent of the mass .

So none of the above are > 2.2s

15) T = 2 pi  m/k = 2 pi  5/1200 = 0.406s

16)