Page 83 - SP015 Past Years PSPM Chapter 6 -14 Ver 2020
P. 83
PSPM SP015
51. f b = 121.9 Hz
52. Frequency heard by a moving observer is 300.41 Hz.
53. (a) f o = 270.3 Hz
54. f a = 1187 Hz
55. f a = 1407 Hz
FINAL ANSWER FOR CHAPTER 11: DEFORMATION OF SOLIDS
F ΔL
1. stress, , strain,
A L o
2. Plastic deformation: Material undergoes permanent extension when stressed or forced beyond its elastic
proportionality limit. When the force is gradually reduces to zero, its stretched length will always be
longer then its original length.
3. Hooke’s law is not applicable in the case of plastic deformation because plastic deformation occurs
beyond the proportionality limit.
1
4. Strong @ elastic @ brittle. F Contact time is increased, impulsive force will decrease.
t
6. Young’s modulus is the ratio of stress to strain if elasticity limit is not exceeded.
10
-2
-2
8
7. (a) break = 1.98 10 N m (b) Y = 7.07 10 N m
8. W = 0.43 J
-5
-5
-5
-4
9. (a) 1 = 2.68 10 , 2 = 8.9 10 (b) L = 5.36 10 m, L = 1.8 10 m
1
2
YA
10. k
L
11
-2
11. (a) Y = 1.77 × 10 N m (b) U = 1.10 J
-1
3
12. k = 3.68 10 N m
13. (a) F = 0.464 N (b) U = 0.0058 J
14. U = 0.294 J
10
15. Y = 2.45 10 Pa
16. The concept of Young’s modulus will be used to determine which rod will bend more.
1
Y Y lower e higher bend more
e
Material with smaller value of Young’s modulus will bend more.
-3
17. = 3.8 10
18. F = 25.8 N
19. U = 3224.5 J
-7
20. U = 9.35 10 J
FINAL ANSWER FOR CHAPTER 12: HEAT CONDUCTION AND THERMAL
EXPANSION
1. Heat is energy transfer due to temperature difference.
Q 1 x
2. k
t A T
3. Factors that influence the thermal conductivity of a conductor is the type of conductor.
7. P loss = 559.4 W
-1
8. (a) Q = 7533 J s (b) T = 101.5 C
9. Q = 21.6 kJ
10. T = 60 C
8
11. Q = 9.24 10 J
12. (a) Temperature of the inner surface of the bulb is 33.3 C.
8
13. Q = 1.66 10 J
14. T j = 130.1 C
15. Coefficient of linear thermal expansion is the fractional increase in length of a solid per unit rise in
temperature.
83
