The main muscles that hold your head upright attach to your spine in back of the point where your head pivots on your neck. The figure provided shows typical numbers for the distance from the pivot to the muscle attachment point and the distance from the pivot to the center of gravity of the head. The muscles pull down to keep your head upright. If the muscle relaxes—if, for instance, you doze in one of your classes besides Physics—your head tips forward. In the questions that follow, assume that your head has a mass of 4.8 kg, and that you maintain the relative angle between your head and your spine.
a) If you tip your body forward so that your spine is level with the ground, what muscle force is needed to keep your head in the same orientation relative to the spine?
b)If you tip your body backward, you will reach a point where no muscle force is needed to keep your head upright. For the distances given in the figure, at what angle does this balance occur?
Homework Answers
Add Answer to:
The main muscles that hold your head upright attach to your
spine in back of the...
When you bend over, a series of large muscles, the erector spinae, pull on your spine to hold you up. (Figure 1) shows...
When you bend over, a series of large muscles, the erector
spine, pull on your spine to hold you up. (Figure 1) 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 360N
weight of the upper torso is at the center of the spine. The 170N
weight of the head and arms acts at the top of the spine. The
erector...
17 BIO A person bending forward to lift a load "with his back" (Fig. P8.17a) rather...
17 BIO A person bending forward to lift a load "with his back" (Fig. P8.17a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, con- sider the model shown in Figure...
17 BIO A person bending forward to lift a load "with his back" (Fig. P8.17a) rather...
17 BIO A person bending forward to lift a load "with his back" (Fig. P8.17a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, con- sider the model shown in Figure...
Even when the head is held erect, as in the figure below, its center of mass...
Even when the head is held erect, as in the figure below, its center of mass is not directly over the principal point of support (the atlanto-occipital joint). The muscles in the back of the neck must therefore exert a force to keep it erect. That is why your head falls forward when you fall asleep in class. If the perpendicular distance between the line of action for the weight of the head and the pivot point is w. -...
A person bending forward to lift a load "with his back" (Figure a) rather than "with...
A person bending forward to lift a load "with his back" (Figure a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, consider the model shown in Figure b, of a...
51. A person bending forward to lift a load "with his back" (Fig. P12.51a) rather than...
51. A person bending forward to lift a load "with his back" (Fig. P12.51a) rather than with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces in- volved, and to understand why back problems are com- mon among humans, consider the model shown in Figure...
kmarks People Window Help Quiz: 95 x 0 Mail - S Power R Cheapo Cheap 0618/quizzes/19056/take...
kmarks People Window Help Quiz: 95 x 0 Mail - S Power R Cheapo Cheap 0618/quizzes/19056/take Questions pus Even when the head is held erect, as in the figure below, its center of mass is not directly over the principal point of support (the atlanto-occipital joint). The muscles in the back of the neck must therefore exert a force to keep it erect. That is why your head falls forward when you fall asleep in class. If the perpendicular distance...
. You are leaning your head over your tissue mechanics book to study as shown in...
. You are leaning your head over your tissue mechanics book to study as shown in the diagram below. E is the erector spinae force, H assume 10% of your body weight from anthropometry tables) is the weight of the head and neck acting downward at their combined center of gravity, and R is the vertebral reaction force acting at a center of pressure on the inferior end plate of C5. Determine the muscle force E and the magnitude and...
You are able to hold out your arm in an outstretched horizontal position because of the action of the deltoid muscle. A...
You are able to hold out your arm in an outstretched horizontal position because of the action of the deltoid muscle. Assume the humerus bone has a mass M1=3.6kg, length L=0.66m and its center of mass is a distance L1=0.33m from the scapula. (For this problem ignore the rest of the arm.) The deltoid muscle attaches to the humerus a distance L2=0.15m from the scapula. The deltoid muscle makes an angle of ?=17? with the horizontal, as shown. (Figure 1)...
When you bend over, a series of large muscles, the erector
spine, pull on your spine to hold you up. (Figure 1) 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 360N
weight of the upper torso is at the center of the spine. The 170N
weight of the head and arms acts at the top of the spine. The
erector...
17 BIO A person bending forward to lift a load "with his back" (Fig. P8.17a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, con- sider the model shown in Figure...
17 BIO A person bending forward to lift a load "with his back" (Fig. P8.17a) rather than "with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces involved, and to understand why back problems are common among humans, con- sider the model shown in Figure...
Even when the head is held erect, as in the figure below, its center of mass is not directly over the principal point of support (the atlanto-occipital joint). The muscles in the back of the neck must therefore exert a force to keep it erect. That is why your head falls forward when you fall asleep in class. If the perpendicular distance between the line of action for the weight of the head and the pivot point is w. -...
51. A person bending forward to lift a load "with his back" (Fig. P12.51a) rather than with his knees" can be injured by large forces exerted on the muscles and vertebrae. The spine pivots mainly at the fifth lumbar vertebra, with the principal supporting force provided by the erector spinalis muscle in the back. To see the magnitude of the forces in- volved, and to understand why back problems are com- mon among humans, consider the model shown in Figure...
kmarks People Window Help Quiz: 95 x 0 Mail - S Power R Cheapo Cheap 0618/quizzes/19056/take Questions pus Even when the head is held erect, as in the figure below, its center of mass is not directly over the principal point of support (the atlanto-occipital joint). The muscles in the back of the neck must therefore exert a force to keep it erect. That is why your head falls forward when you fall asleep in class. If the perpendicular distance...
. You are leaning your head over your tissue mechanics book to study as shown in the diagram below. E is the erector spinae force, H assume 10% of your body weight from anthropometry tables) is the weight of the head and neck acting downward at their combined center of gravity, and R is the vertebral reaction force acting at a center of pressure on the inferior end plate of C5. Determine the muscle force E and the magnitude and...
Most questions answered within 3 hours.
-
A solid, uniform disk of radius 0.250 m and mass 53.7 kg rolls
down a ramp...
asked 1 hour ago -
Given the following table of high speed internet access vs.
annual home income:
Home Income
%...
asked 1 hour ago -
A baseball batter hits a 0.145kg baseball straight up into the
air. The baseball leaves the...
asked 2 hours ago -
An FM modulator is tested using
single-tone baseband signal with frequency of 50kHz and a sprectrum...
asked 2 hours ago -
Write the ionic equations for the first stage of salts
hydrolysis.
Anion, Cation?
Na2S
NiSO4
K2SO4...
asked 4 hours ago -
suppose there is a normally distributed population with a mean of
250 and a standard deviation...
asked 4 hours ago -
Question Three
Suppose you as project manager are using the Waterfall
development methodology on a large...
asked 5 hours ago -
Which statement is not true about welfare in Canada?
A.Benefits typically vary based on one's ability...
asked 6 hours ago -
Please help me with FLOWCHART and UML diagram for class,
thank you!
#include <iostream>
#include <fstream>...
asked 7 hours ago -
3. Describe the “logic circuit” of the Lac operon. Which
proteins are bound or not to...
asked 7 hours ago -
Ayesha’s adjusted gross income is $60,000 in 2019. She donated a
piece of artwork with a...
asked 7 hours ago -
For Dijkstra’s shortest path algorithm:
a. Give the Big-O time for Dijkstra’s shortest path algorithm
and...
asked 7 hours ago