Skip to main content
Ch. 6 - Applications of Integration
Briggs - Calculus: Early Transcendentals 3rd Edition
Briggs3rd EditionCalculus: Early TranscendentalsISBN: 9780136847243당신이 사용하는 게 아니라요?교과서 변경
6장, 문제 6.7.18

13–20. Mass of one-dimensional objects Find the mass of the following thin bars with the given density function.


ρ(x) = {1 if 0≤x≤2 {2 if 2<x≤3

검증된 단계별 안내
1
Identify the density function \( \rho(x) \) given as a piecewise function: \( \rho(x) = 1 \) for \( 0 \leq x \leq 2 \) and \( \rho(x) = 2 \) for \( 2 < x \leq 3 \).
Recall that the mass \( m \) of a thin bar along the x-axis with density function \( \rho(x) \) is found by integrating the density over the length of the bar: \( m = \int_a^b \rho(x) \, dx \).
Since the density function changes at \( x=2 \), split the integral into two parts: \( m = \int_0^2 1 \, dx + \int_2^3 2 \, dx \).
Set up each integral separately: the first integral calculates the mass from 0 to 2 with density 1, and the second integral calculates the mass from 2 to 3 with density 2.
Evaluate each integral by integrating the constant densities over their respective intervals, then sum the results to find the total mass of the bar.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
2m

주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Density Function

The density function ρ(x) describes how mass is distributed along the length of the bar. It can vary with position x, indicating that different segments of the bar may have different mass per unit length. Understanding this function is essential to calculate the total mass accurately.
추천 영상:
가이드 코스
06:21
Properties of Functions

Definite Integral for Mass

The total mass of a one-dimensional object with variable density is found by integrating the density function over the object's length. This involves computing the definite integral of ρ(x) with respect to x over the given intervals, summing contributions from each segment.
추천 영상:
가이드 코스
05:43
Definition of the Definite Integral

Piecewise Functions

When the density function is defined differently over separate intervals, it is called a piecewise function. To find the total mass, you must integrate each piece over its respective interval and then add the results, ensuring correct handling of the function's discontinuities.
추천 영상:
가이드 코스
05:36
Piecewise Functions