Concept explainers
(a)
The stretched length of hair.
Answer to Problem 75QAP
The stretched length of hair is
Explanation of Solution
Given:
Original length of hair
Total active weight of object
Radius of hair
Area of cross-section of hair
Young's Modulus of hair
Let
Formula used:
Young's Modulus
Here, all alphabets are in their usual meanings.
Calculation:
Substituting the given values in the formula,
Hence, the stretched length of hair is
Conclusion:
Thus, the stretched length of hair is
(b)
The stretched length of aluminum wire.
Answer to Problem 75QAP
The stretched length of aluminum wire is
Explanation of Solution
Given:
The stretched length of hair
Young's Modulus of hair
Young's Modulus of aluminum wire
Let
Formula used:
Young's Modulus
Here, all alphabets are in their usual meanings.
Calculation:
Substituting the given values in the formula,
Hence, the stretched length of aluminum wire is
Conclusion:
Thus, the stretched length of aluminum wire is
(c)
The spring constant of hair.
Answer to Problem 75QAP
The spring constant of hair is
Explanation of Solution
Given:
The stretched length of hair
Total active weight of object
Let 'k' be the spring constant
Formula used:
Apply Hooke's Law,
Weight of object
Here, all alphabets are in their usual meanings.
Calculation:
Apply Hooke's Law,
Weight of object
Hence, the spring constant of hair is
Conclusion:
Thus, the spring constant of hair is
(d)
To compare the spring constant of hair with the spring constant in laboratory.
Answer to Problem 75QAP
The spring constant of hair is about
Explanation of Solution
Given:
The spring constant of hair
The spring constant wire in laboratory (say)
Formula used:
Ratio of the spring constant
Here, all alphabets are in their usual meanings.
Calculation:
Substituting the given values in the formula,
Hence, the spring constant of hair is about
Conclusion:
Thus, the spring constant of hair is about
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Chapter 9 Solutions
COLLEGE PHYSICS
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