Lesson_4.6_Homework_Solution

# Lesson_4.6_Homework_Solution - Lesson 4.6 Homework...

This preview shows pages 1–3. Sign up to view the full content.

Lesson 4.6 Homework Solutions 1. A 200-kg mass is suspended from the end of a 2.5-m cable with a diameter of 1.6 cm. (i) Calculate the stress in the cable. (ii) If the wire stretches by 0.48 mm under this stress, what is the strain produced? (iii) What is the Young’s modulus of the material of the wire? The force pulling the cable is 200 kg × 9.8 ms -2 = 1960 N The radius of the cable is: r = 0.8 cm = 0.008 m The area of cross section of the cable is: A = π r 2 = π × (0.008) 2 = 2.01 × 10 -4 m 2 4 6 2 1960 N (i) 2.01 10 9.75 10 Nm F Stress A - - = = = × × (ii) L = 2.5 m, L = 0.48 mm = 0.48 × 10 -3 m 5 3 0.48 10 1.92 10 m 2.5 L Strain L m - - × = × = = 6 -2 1 5 1 2 Stress 9.75 10 Nm (iii) Strain 1.9 5.08 10 2 10 Nm y - - × × = = = × 2. When a cylindrical plastic strip 22 cm long is stretched by a force of 15.8 N applied at one of its ends, its length increases by 5.9 mm. If the average diameter of the strip is 6.8 mm, calculate the Young’s modulus of elasticity of the material of the strip. Area of cross section = π r 2 = π (3.4 x 10 -3 ) 2 = 3.6 x 10 -5 m 2 5 2 5 3 2 2 7 2 5 15.8 4.4 10 3.6 10 5.9 10 0.027 22 1.6 10 10 4.4 10 0.027 F Stress Nm A L Strain L stes Nm s Nm Y strain - - - - - - = = = × × × = = = = × × × = =

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
3. How much pressure is needed to compress the volume of an
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 05/01/2011 for the course PHY 2048 taught by Professor George during the Fall '10 term at Edison State College.

### Page1 / 5

Lesson_4.6_Homework_Solution - Lesson 4.6 Homework...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online