Physics for Scientists and Engineers With Modern Physics
9th Edition
ISBN: 9781133953982
Author: SERWAY, Raymond A./
Publisher: Cengage Learning
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Question
Chapter 12, Problem 12P
(a)
To determine
The magnitudes of
(b)
To determine
The magnitudes of
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
1.65 m
F
g1
F
g2
26. In exercise physiology studies, it is sometimes important to
BIO determine the location of a person's center of mass. This
V determination can be done with the arrangement shown in
Figure P12.26. A light plank rests on two scales, which read
= 380 N and F, = 320 N. A distance of 1.65 m sepa-
rates the scales. How far from the woman's feet is her center
of mass?
Do Chapter 12, Problem 26. This is one way to
measure a person's center of mass. She lies on a
plank on two scales: one at her head, the other at
her feet. They are 1.71 meters apart. Her head
scale reads 378 N, and her foot scale reads 389 N.
How far from her feet is her center of mass?
12
When you bend over, a series of large muscles, the erector spinae, pull on your spine to hold you up. The following figure shows a simplified model of the spine as a rod of length L that pivots at its lower end. In this model, the center of gravity of the 270 N270 N weight of the upper torso is at the center of the spine. The 140 N140 N weight of the head and arms acts at the top of the spine. The erector spinae muscles are modeled as a single muscle that acts at a 1212-degree angle to the spine. Suppose the person in the figure bends over to an angle of 3030 degrees from horizontal.
The center of gravity is half the length, and the center of gravity for the upper torso is 2/32/3 of the length
A. What is the tension in the erector muscle?
B. A force from the pelvic girdle acts on the base of the spine. What is the component of this force in the direction parallel to the spine? This large force is the cause of many back injuries.
Chapter 12 Solutions
Physics for Scientists and Engineers With Modern Physics
Ch. 12.1 - Consider the object subject to the two forces of...Ch. 12.1 - Consider the object subject to the three forces in...Ch. 12.2 - A meterstick of uniform density is hung from a...Ch. 12.4 - For the three parts of this Quick Quiz, choose...Ch. 12 - Prob. 1OQCh. 12 - Prob. 2OQCh. 12 - Prob. 3OQCh. 12 - Prob. 4OQCh. 12 - In the cabin of a ship, a soda can rests in a...Ch. 12 - Prob. 6OQ
Ch. 12 - Prob. 7OQCh. 12 - Prob. 8OQCh. 12 - Prob. 9OQCh. 12 - Prob. 10OQCh. 12 - Prob. 1CQCh. 12 - Prob. 2CQCh. 12 - Prob. 3CQCh. 12 - Prob. 4CQCh. 12 - Prob. 5CQCh. 12 - Prob. 6CQCh. 12 - Prob. 7CQCh. 12 - What kind of deformation does a cube of Jell-O...Ch. 12 - Prob. 1PCh. 12 - Why is the following situation impossible? A...Ch. 12 - Prob. 3PCh. 12 - Prob. 4PCh. 12 - Your brother is opening a skateboard shop. He has...Ch. 12 - A circular pizza of radius R has a circular piece...Ch. 12 - Prob. 7PCh. 12 - Prob. 8PCh. 12 - Prob. 9PCh. 12 - Prob. 10PCh. 12 - A uniform beam of length 7.60 m and weight 4.50 ...Ch. 12 - Prob. 12PCh. 12 - Prob. 13PCh. 12 - A uniform ladder of length L and mass m1 rests...Ch. 12 - A flexible chain weighing 40.0 N hangs between two...Ch. 12 - A uniform beam of length L and mass m shown in...Ch. 12 - Figure P12.13 shows a claw hammer being used to...Ch. 12 - A 20.0-kg floodlight in a park is supported at the...Ch. 12 - Prob. 19PCh. 12 - Review. While Lost-a-Lot ponders his next move in...Ch. 12 - John is pushing his daughter Rachel in a...Ch. 12 - Prob. 22PCh. 12 - Prob. 23PCh. 12 - A 10.0-kg monkey climbs a uniform ladder with...Ch. 12 - Prob. 25PCh. 12 - A steel wire of diameter 1 mm can support a...Ch. 12 - The deepest point in the ocean is in the Mariana...Ch. 12 - Assume Youngs modulus for bone is 1.50 1010 N/m2....Ch. 12 - A child slides across a floor in a pair of...Ch. 12 - Evaluate Youngs modulus for the material whose...Ch. 12 - Prob. 31PCh. 12 - When water freezes, it expands by about 9.00%....Ch. 12 - Prob. 33PCh. 12 - Prob. 34PCh. 12 - Prob. 35PCh. 12 - Review. A 30.0-kg hammer, moving with speed 20.0...Ch. 12 - A bridge of length 50.0 m and mass 8.00 104 kg is...Ch. 12 - A uniform beam resting on two pivots has a length...Ch. 12 - Prob. 39APCh. 12 - The lintel of prestressed reinforced concrete in...Ch. 12 - Prob. 41APCh. 12 - When a person stands on tiptoe on one foot (a...Ch. 12 - A hungry bear weighing 700 N walks out on a beam...Ch. 12 - Prob. 44APCh. 12 - A uniform sign of weight Fg and width 2L hangs...Ch. 12 - Prob. 46APCh. 12 - Prob. 47APCh. 12 - Assume a person bends forward to lift a load with...Ch. 12 - A 10 000-N shark is supported by a rope attached...Ch. 12 - Prob. 50APCh. 12 - A uniform beam of mass m is inclined at an angle ...Ch. 12 - Prob. 52APCh. 12 - When a circus performer performing on the rings...Ch. 12 - Figure P12.38 shows a light truss formed from...Ch. 12 - Prob. 55APCh. 12 - A stepladder of negligible weight is constructed...Ch. 12 - A stepladder of negligible weight is constructed...Ch. 12 - Prob. 58APCh. 12 - Two racquetballs, each having a mass of 170 g, are...Ch. 12 - Review. A wire of length L, Youngs modulus Y, and...Ch. 12 - Review. An aluminum wire is 0.850 m long and has a...Ch. 12 - Prob. 62APCh. 12 - A 500-N uniform rectangular sign 4.00 m wide and...Ch. 12 - A steel cable 3.00 cm2 in cross-sectional area has...Ch. 12 - Prob. 65CPCh. 12 - In the What If? section of Example 12.2, let d...Ch. 12 - Prob. 67CPCh. 12 - A uniform rod of weight Fg and length L is...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- Why is the following situation impossible? A uniform beam of mass mk = 3.00 kg and length = 1.00 m supports blocks with masses m1 = 5.00 kg and m2 = 15.0 kg at two positions as shown in Figure P12.2. The beam rests on two triangular blocks, with point P a distance d = 0.300 m to the right of the center of gravity of the beam. The position of the object of mass m2 is adjusted along the length of the beam until the normal force on the beam at O is zero. Figure P12.2arrow_forwardA massless, horizontal beam of length L and a massless rope support a sign of mass m (Fig. P14.78). a. What is the tension in the rope? b. In terms of m, g, d, L, and , what are the components of the force exerted by the beam on the wall? FIGURE P14.78arrow_forwardRuby, with mass 55.0 kg, is trying to reach a box on a high shelf by standing on her tiptoes. In this position, half her weight is supported by the normal force exerted by the floor on the toes of each foot as shown in Figure P14.75A. This situation can be modeled mechanically by representing the force on Rubys Achilles tendon with FA and the force on her tibia as FT as shown in Figure P14.75B. What is the value of the angle and the magnitudes of the forces FA and FT? FIGURE P14.75arrow_forward
- A uniform beam of length 7.60 m and weight 4.50 102 N is carried by two workers, Sam and Joe, as shown in Figure P12.6. Determine the force that each person exerts on the beam. Figure P12.6arrow_forwardWhen a circus performer performing on the rings executes the iron cross, he maintains the position at rest shown in Figure P12.37a. In this maneuver, the gymnasts feet (not shown) are off the floor. The primary muscles involved in supporting this position are the latissimus dorsi (lats) and the pectoralis major (pecs). One of the rings exerts an upward force Fk on a hand as show n in Figure P12.37b. The force Fs, is exerted by the shoulder joint on the arm. The latissimus dorsi and pectoralis major muscles exert a total force Fm on the arm. (a) Using the information in the figure, find the magnitude of the force Fm for an athlete of weight 750 N. (b) Suppose a performer in training cannot perform the iron cross but can hold a position similar to the figure in which the arms make a 45 angle with the horizontal rather than being horizontal. Why is this position easier for the performer? Figure P12.37arrow_forwardAt a museum, a 1300-kg model aircraft is hung from a lightweight beam of length 12.0 m that is free to pivot about its base and is supported by a massless cable (Fig. P14.38). Ignore the mass of the beam. a. What is the tension in the section of the cable between the beam and the wall? b. What are the horizontal and vertical forces that the pivot exerts on the beam? FIGURE P14.38 (a) From the free-body diagram, the angle that the string tension makes with the beam is = 55.0 + 18.0 = 73.0, and the perpendicular component of the string tension is FT sin73.0. Summing torques around the base of the rod gives (Eq. 14.2): =0:(12.0m)(1300kg)(9.81m/s2)cos55.0+FT(12.0m)sin73.0=0FT=(12.0m)(1300kg)(9.81m/s2)cos55.0(12.0m)sin73.0FT=7.65103N Figure P14.38ANS (b) Using force balance (Eq. 14.1): Fx=0:FHFTcos18.0=0FH=FTcos18.0=[(12.0m)(1300kg)(9.81m/s2)cos55.0(12.0m)sin73.0]cos18.0=7.27103NFy=0:FVFTsin18.0(1300kg)(9.81m/s2)=0 FV=FTsin18.0+(1300kg)gFV=[(12.0m)(1300kg)(9.81m/s2)cos55.0(12.0m)sin73.0]sin18.0+(1300kg)(9.81m/s2)FV=1.51104Narrow_forward
- A stepladder of negligible weight is constructed as shown in Figure P12.40, with AC = BC = . A painter of mass m stands on the ladder a distance d from the bottom. Assuming the floor is frictionless, find (a) the tension in the horizontal bar DE connecting the two halves of the ladder, (b) the normal forces at A and B, and (c) the components of the reaction force at the single hinge C that the left half of the ladder exerts on the right half. Suggestion: Treat the ladder as a single object, but also treat each half of the ladder separately. Figure P12.40 Problems 40 and 41.arrow_forwardConsider a nanotube with a Youngs modulus of 2.130 1012 N/m2 that experiences a tensile stress of 5.3 1010 N/m2. Steel has a Youngs modulus of about 2.000 1011 Pa. How much stress would cause a piece of steel to experience the same strain as the nanotube?arrow_forwardA person carries a plank of wood 2.00 m long with one hand pushing down on it at one end with a force F1 and the other hand holding it up at .500 m from the end of the plank with force F2. If the plank has a mass of 20.0 kg and its center of gravity is at the middle of the plank, what are the magnitudes of the forces F1 and F2?arrow_forward
- Children playing pirates have suspended a uniform wooden plank with mass 15.0 kg and length 2.50 m as shown in Figure P14.27. What is the tension in each of the three ropes when Sophia, with a mass of 23.0 kg, is made to walk the plank and is 1.50 m from reaching the end of the plank? FIGURE P14.27arrow_forwardA stepladder of negligible weight is constructed as shown in Figure P12.40, with AC = BC = = 4.00 m. A painter of mass m = 70.0 kg stands on the ladder d = 3.00 m from the bottom. Assuming the floor is frictionless, find (a) the tension in the horizontal bar DE connecting the two halves of the ladder, (b) the normal forces at A and B, and (c) the components of the reaction force at the single hinge C that the left half of the ladder exerts on the right half. Suggestion: Treat the ladder as a single object, but also treat each half of the ladder separately. Figure P12.40 Problems 40 and 41.arrow_forwardA rod of length 4.00 m with negligible mass is hinged to a wall. A rope attached to the end of the rod runs up to the wall at an angle of exactly 45, helping support the rod, while a sign of weight 10.0 N is hanging by two ropes attached to the bottom of the rod. The ropes make an angle of exactly 30 with the rod as shown in Figure P14.79. Another sign with a weight of 10.0 N is attached to the top of the rod with its center of mass at the midpoint of the rod. The entire system is in equilibrium. Find the magnitude of the tension in the rope above the rod that is also attached to the wall. FIGURE P14.79 Problems 79 and 80.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax College
Physics for Scientists and EngineersPhysicsISBN:9781337553278Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Physics for Scientists and Engineers with Modern ...PhysicsISBN:9781337553292Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning
College PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning
College Physics
Physics
ISBN:9781938168000
Author:Paul Peter Urone, Roger Hinrichs
Publisher:OpenStax College
Physics for Scientists and Engineers
Physics
ISBN:9781337553278
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers with Modern ...
Physics
ISBN:9781337553292
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
College Physics
Physics
ISBN:9781285737027
Author:Raymond A. Serway, Chris Vuille
Publisher:Cengage Learning
SIMPLE HARMONIC MOTION (Physics Animation); Author: EarthPen;https://www.youtube.com/watch?v=XjkUcJkGd3Y;License: Standard YouTube License, CC-BY