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Homework5.docxChapter 5 - Elasticity 10 questions
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Question 1
What is Elasticity (formal definition)?Bottom of Form
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Question 2
If a body, under the action of a force, is distorted beyond its elastic limit, will the original shape restored after removal of the force?Bottom of Form
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Question 3
A bar of steel. with radius 12 mm, is under the action of an axial force of 130 N.
a. Find the normal stress, Sn (express your answer in MPa, given that: 1 N/mm^2 = 1 MPa)
b. If the Tensile Strength of the steel is 350 MPa (yield limit), is this bar going to fail?
Question 4
A bar under the action of an axial force F, suffer a variation in length as is represented below:
a. Find the normal Strain
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Question 5
When a force is considered an "impulsive Force"?Bottom of Form
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Question 6
A car with a mass of 1100 kg at 50 mph, driving toward the East, have collision and rebound (toward West) with a velocity of 7 mph. Find the Average Value of the Impulsive Force (F av) If the duration of the collision is 4 × 10^-3 seconds. (Convert the mph to m/s)
1mph = 0.447 m/s
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Question 7
The average impulsive force due to a fall is:
If a person with mass 67 kg, fall from a roof with height 2.9 m, and the impact time is estimated in 2 x 10 ^ -2 seconds.
a. Find the Average Impulsive Force
If the combined area of his 2 leg bones is 5.8 cm^2 (convert in m^2).
b. Find the Compressive normal stress acting in his legs
If the rupture strength of the bones is 1.0 x 10^8 Pa (1 Pa = 1 N/m^2)
c. Should the bones of his legs fracture due to the fall? Explain.
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Question 8
What is the role of the airbags during a car collision?Bottom of Form
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Question 9
The force acting on a person due to the deceleration of a car (from initial velocity v = v0 to final velocity v = 0, is given by the formula:
If the mass of a person is 90 kg, the velocity of the car is 60 mph and the stopping distance of the person when move forward due to the Inertia is 28 cm.
a. Find the Average Force of the Impact
b. If the force is uniformly distributed over an area of 900 cm^2. What is the Normal Stress on the person/s body?
c. If the Compressive Strength of Human Tissue is 6 x 10^5 Pa, is the person going to survive the impact without severe damage?
1 mph = 0.447 m/s
1m = 100 cm
1 N/m^2 = 1 Pa
1 m^2 = 10,000 cm^2Bottom of Form
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Question 10
Read the article:
Write a summary of less than 500 words of the findings by the Authors
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