재료역학 4판 솔루션 (저자 Ferdunand P. Beer , 4th ed Mechanics of Materials)

Chapter 1
1. Various geometric formulas are given in Appendix E. (a) Expressing the radius of the Earth as

R 〓 ( 6.37 × 106 m )(10?3 km m ) 〓 6.37 × 103 km, its circumference is s 〓 2π R 〓 2π (6.37 × 103 km) 〓 4.00 × 104 km. (b) The surface area of Earth is A 〓 4π R 2 〓 4π ( 6.37 × 103 km ) 〓 5.10 × 108 km 2 .
2

(c) The volume of Earth is V 〓

4 π 3 4π R 〓 6.37 × 103 km 3 3

(

)

3

〓 1.08 × 1012 km3 .

2. The conversion factors are: 1 gry 〓 1/10 line , 1 line 〓 1/12 inch and 1 point 〓 1/72 inch. The factors imply that 1 gry 〓 (1/10)(1/12)(72 points) 〓 0.60 point. Thus, 1 gry2 〓 (0.60 point)2 〓 0.36 point2, which means that 0.50 gry 2 〓 0.18 point 2 . 3. The metric prefixes (micro, pico, nano, …) are given for ready reference on the inside front cover of the textbook (see also Table 1?2). (a) Since 1 km 〓 1 × 103 m and 1 m 〓 1 × 106 μm,

1km 〓 103 m 〓 103 m 106 μ m m 〓 109 μ m. The given measurement is 1.0 km (two signi…