age 111 Practice Problem 4.8: If we double the mass of the chain, what are the new values for e magnitude of the tension forces at both ends of the chain? Answer: T₁= 2156 N; T₂- 1960 N.

Elements Of Electromagnetics
7th Edition
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Sadiku, Matthew N. O.
ChapterMA: Math Assessment
Section: Chapter Questions
Problem 1.1MA
icon
Related questions
Question
The second photo has background info to help solve the practice problem
Page 111 Practice Problem 4.8: If we double the mass of the chain, what are the new values for
the magnitude of the tension forces at both ends of the chain? Answer: T₁= 2156 N; T₂= 1960 N.
Transcribed Image Text:Page 111 Practice Problem 4.8: If we double the mass of the chain, what are the new values for the magnitude of the tension forces at both ends of the chain? Answer: T₁= 2156 N; T₂= 1960 N.
EXAMPLE 4.8 Tension in a chain with mass
Now suppose that the mass of the chain in Example 4.7 is not negligible, but is 10.0 kg. Again, let's find the
forces at the ends of the chain.
SOLUTION
SET UP Again
we draw separate free-body diagrams for the re-
flector and the chain (Figure 4.27); each is in equilibrium. We take
the y axis to be vertically upward. The weight wc of the chain is
wc = mc8 = (10.0 kg) (9.8 m/s²) = 98 N. The free-body diagrams
are different from those in Figure 4.26 because the magnitudes of the
forces acting on the two ends of the chain are no longer equal. (Other-
wise, the chain couldn't be in equilibrium.) We label these two forces
T₁ and T₂.
SOLVE Note that the two forces labeled T₂ form an action-reaction
pair; that's how we know that they have the same magnitude. The equi-
librium condition ΣΕ = 0 for the reflector is
T₂ + (-1960 N) = 0,
SO T₂ = 1960 N.
There are now three forces acting on the chain: its weight and the forces
at the two ends. The equilibrium condition EF, = 0 for the chain is
T₁ + (-1₂) + (-98 N) = 0.
Note that the y component of T₁ is positive because it points in the
+y direction, but the y components of both T2 and 98 N are negative.
When we substitute the value T₂ = 1960 N and solve for T₁, we find
that
T₁ = 2058 N.
Alternative Solution: An alternative procedure is to draw a free-body
diagram for the composite object consisting of the reflector and the
chain together (Figure 4.27b). The two forces on this composite object
are the upward force T₁ at the top of the chain and the total weight,
with magnitude 1960 N +98 N = 2058 N. Again, we find that
100
T
Yonde
Pas d'andat
WR
5010
WC
(a) Free-body diagrams for
reflector and chain
ASI 202
Video Tutor Solution
Reflector +
Chain
We + WC
(b) Free-body diagram for reflector
and chain treated as a unit
A FIGURE 4.27 Two alternative diagrams we could draw for
this problem.
T₁= 2058 N. Note that we cannot find T2 by this method; we still need
a separate free-body diagram for one of the objects.
REFLECT When a composite object can be divided into two or more
component parts, there are usually several alternative solutions. Often,
the calculations can be simplified by a clever choice of subsystems.
Also, solving a problem in two or more alternative ways provides a
consistency check that's useful in finding errors.
Practice Problem: If we double the mass of the chain, what are the
new values for the magnitude of the tension forces at both ends of the
chain? Answer: T₁ = 2156 N; T₂ = 1960 N.
Transcribed Image Text:EXAMPLE 4.8 Tension in a chain with mass Now suppose that the mass of the chain in Example 4.7 is not negligible, but is 10.0 kg. Again, let's find the forces at the ends of the chain. SOLUTION SET UP Again we draw separate free-body diagrams for the re- flector and the chain (Figure 4.27); each is in equilibrium. We take the y axis to be vertically upward. The weight wc of the chain is wc = mc8 = (10.0 kg) (9.8 m/s²) = 98 N. The free-body diagrams are different from those in Figure 4.26 because the magnitudes of the forces acting on the two ends of the chain are no longer equal. (Other- wise, the chain couldn't be in equilibrium.) We label these two forces T₁ and T₂. SOLVE Note that the two forces labeled T₂ form an action-reaction pair; that's how we know that they have the same magnitude. The equi- librium condition ΣΕ = 0 for the reflector is T₂ + (-1960 N) = 0, SO T₂ = 1960 N. There are now three forces acting on the chain: its weight and the forces at the two ends. The equilibrium condition EF, = 0 for the chain is T₁ + (-1₂) + (-98 N) = 0. Note that the y component of T₁ is positive because it points in the +y direction, but the y components of both T2 and 98 N are negative. When we substitute the value T₂ = 1960 N and solve for T₁, we find that T₁ = 2058 N. Alternative Solution: An alternative procedure is to draw a free-body diagram for the composite object consisting of the reflector and the chain together (Figure 4.27b). The two forces on this composite object are the upward force T₁ at the top of the chain and the total weight, with magnitude 1960 N +98 N = 2058 N. Again, we find that 100 T Yonde Pas d'andat WR 5010 WC (a) Free-body diagrams for reflector and chain ASI 202 Video Tutor Solution Reflector + Chain We + WC (b) Free-body diagram for reflector and chain treated as a unit A FIGURE 4.27 Two alternative diagrams we could draw for this problem. T₁= 2058 N. Note that we cannot find T2 by this method; we still need a separate free-body diagram for one of the objects. REFLECT When a composite object can be divided into two or more component parts, there are usually several alternative solutions. Often, the calculations can be simplified by a clever choice of subsystems. Also, solving a problem in two or more alternative ways provides a consistency check that's useful in finding errors. Practice Problem: If we double the mass of the chain, what are the new values for the magnitude of the tension forces at both ends of the chain? Answer: T₁ = 2156 N; T₂ = 1960 N.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps

Blurred answer
Knowledge Booster
Basic Mechanics Problems
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Elements Of Electromagnetics
Elements Of Electromagnetics
Mechanical Engineering
ISBN:
9780190698614
Author:
Sadiku, Matthew N. O.
Publisher:
Oxford University Press
Mechanics of Materials (10th Edition)
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:
9780134319650
Author:
Russell C. Hibbeler
Publisher:
PEARSON
Thermodynamics: An Engineering Approach
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:
9781259822674
Author:
Yunus A. Cengel Dr., Michael A. Boles
Publisher:
McGraw-Hill Education
Control Systems Engineering
Control Systems Engineering
Mechanical Engineering
ISBN:
9781118170519
Author:
Norman S. Nise
Publisher:
WILEY
Mechanics of Materials (MindTap Course List)
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:
9781337093347
Author:
Barry J. Goodno, James M. Gere
Publisher:
Cengage Learning
Engineering Mechanics: Statics
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:
9781118807330
Author:
James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:
WILEY