11_InstSolManual_PDF_Part1

11_InstSolManual_PDF_Part1 - ELASTICITY AND PERIODIC MOTION...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: ELASTICITY AND PERIODIC MOTION 11 9. C 10. C 11. B 12. C 13. B 14. D 15. C Answers to Multiple-Choice Problems 1. A 2. B 3. B 4. A 5. C 6. C 7. A, C, D 8. B Solutions to Problems mg 5 1 25.0 kg 2 1 9.80 m / s2 2 5 245 N. stress 5 FT / A and strain 5 D l / l0 . Y 5 stress / strain 245 N 5 1.03 3 109 Pa Solve: (a) stress 5 p 1 2.75 3 1024 m 2 2 1.10 3 1023 m (b) strain 5 D l / l0 5 5 1.47 3 1023 0.750 m 1.03 3 109 Pa stress (c) Y 5 5 5 7.01 3 1011 Pa strain 1.47 3 1023 Reflect: Our result for Y is about the same size as the values in Table 11.1. In SI units the stress is very large. The strain is dimensionless and small, so Y is very large and has the same units (Pa) as stress. 11.1. Set Up: A 5 p r 2, with r 5 2.75 3 1024 m . The force FT applied to the end of the wire is 11.2. Set Up: A 5 0.50 cm 2 5 0.50 3 1024 m 2 Solve: Y 5 the end of the post is F' 5 1 8000 kg 2 1 9.80 m / s2 2 5 7.84 3 104 N . The Young’s modulus of steel is Y 5 2.0 3 1011 Pa. F' 7.84 3 104 N Solve: (a) stress 5 5 5 1.60 3 106 Pa A 0.0491 m 2 stress 1.60 3 106 Pa 52 5 2 8.0 3 1026. The minus sign indicates that the length decreases. (b) strain 5 Y 2.0 3 1011 Pa (c) D l 5 l0 1 strain 2 5 1 2.50 m 2 1 2 8.0 3 1026 2 5 2 2.0 3 1025 m 98.0 N. The force applied to the end of the upper wire is 1 5.0 kg 1 10.0 kg 2 1 9.80 m / s2 2 5 147.0 N. Tensile F' Dl 5 . strain 5 l0 AY 11.3. Set Up: The cross-sectional area of the post is A 5 p r 2 5 p 1 0.125 m 2 2 5 0.0491 m 2. The force applied to 1 4.00 m 2 1 5000 N 2 l0 F' 5 5 2.0 3 1011 Pa 1 0.50 3 1024 m 2 2 1 0.20 3 1022 m 2 A Dl 11.4. Set Up: For steel, Y 5 2.0 3 1011 Pa. The force applied to the end of the lower wire is 1 10.0 kg 2 1 9.80 m / s2 2 5 11-1 ...
View Full Document

This note was uploaded on 03/06/2009 for the course PHYS 114 taught by Professor Shoberg during the Spring '07 term at Pittsburg State Uiversity.

Ask a homework question - tutors are online