College Physics
2nd Edition
ISBN: 9780134601823
Author: ETKINA, Eugenia, Planinšič, G. (gorazd), Van Heuvelen, Alan
Publisher: Pearson,
expand_more
expand_more
format_list_bulleted
Concept explainers
Textbook Question
Chapter 8, Problem 49GP
BIO Using triceps to push a table A man pushes on a table exerting a 20-N downward force with his hand. Determine the force that his triceps muscle must exert on his forearm in order to balance the upward force that the table exerts on his hand. Ignore the biceps muscle and the mass of the arm. If you did not ignore the mass of the arm, would the force you determined be smaller or larger? Explain.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
Consider the following figure.
a.
What force in newtons should the woman in the figure exert on the floor with each hand to do a push-up? Assume that she moves up at a constant speed.
_______ N
b.
The triceps muscle at the back of her upper arm has an effective lever arm of 1.76 cm, and she exerts force on the floor at a horizontal distance of 18.0 cm from the elbow joint. Calculate the magnitude of the force in newtons in each triceps muscle.
_________ N
Compare the magnitude of the total force exerted by both triceps muscles to her weight.
total force exerted by both triceps muscles/her weight =
c. How much work does she do in joules if her center of mass rises 0.255 m?
_______ J
d.
What is her useful power output in watts if she does 21 push-ups in one minute?
_______ W
A. Explain why placing your hands behind your head rather than placing them on your stomach makes sit-ups more difficult.
B. Explain why it is easier (it requires a smaller force) to open a large jar than a small one.
To determine the force a person's triceps muscle can
exert, a doctor uses the procedure shown in the figure(
Figure 1), where the patient pushes down with the palm
of his hand on a force meter.
4
Figure
FT
Humerus
-Triceps
Axis
Radius
2.78 cm
-18.6 cm-
Ulna
Mg
Chapter 8 Solutions
College Physics
Ch. 8 - Prob. 1RQCh. 8 - Review Question 8.2 Give an example of a situation...Ch. 8 - Review Question 8.3 You read the following...Ch. 8 - Prob. 4RQCh. 8 - Review Question 8.5 You are trying to hold a heavy...Ch. 8 - Review Question 8.6 Why is a ball hanging by a...Ch. 8 - A falling leaf usually flutters while falling....Ch. 8 - Prob. 2MCQCh. 8 - A hammock is tied with ropes between two trees. A...Ch. 8 - Prob. 4MCQ
Ch. 8 - 5. A physics textbook lies on top of a chemistry...Ch. 8 - What does it mean if the torque of a force is...Ch. 8 - Prob. 7MCQCh. 8 - 8. Why do you tilt your body forward when hiking...Ch. 8 - 9. What does it mean if the torque of a 10-N force...Ch. 8 - What is the maximum angle to the horizontal you...Ch. 8 - Prob. 11MCQCh. 8 - 12. Is it possible for an object not to be in...Ch. 8 - Explain the meaning of torque so that a friend not...Ch. 8 - Prob. 14CQCh. 8 - What are the two conditions of equilibrium? What...Ch. 8 - Give three examples of situations in which an...Ch. 8 - The force that the body muscles exert on bones...Ch. 8 - A ladder leans against a wall. Construct a force...Ch. 8 - Using a crowbar, a person can remove a nail by...Ch. 8 - 20. Is it more difficult to do a sit-up with your...Ch. 8 - Sit on a chair with your feet straight down at the...Ch. 8 - Can you balance the tip of a wooden ruler...Ch. 8 - Try to balance a sharp wooden pencil on your...Ch. 8 - 24. Design a device that you can use to...Ch. 8 - Explain why it is easier to keep your balance...Ch. 8 - A carpenters trick to keep nails from bending when...Ch. 8 - Determine the torques about the axis of rotation P...Ch. 8 - 2. Three 200-N forces are exerted on the beam...Ch. 8 - 3. * A 2.0-m-long, 15-kg ladder is resting against...Ch. 8 - Figure P8.4 shows two different situations where...Ch. 8 - Three friends tie three ropes in a knot and pull...Ch. 8 - Prob. 6PCh. 8 - * Kate joins Jim, Luis, and Adrienne in the...Ch. 8 - You hang a light in front of your house using an...Ch. 8 - * Find the values of the forces the ropes exert on...Ch. 8 - Prob. 10PCh. 8 - Determine the masses m1 and m2 of the two objects...Ch. 8 - * Lifting an engine You work in a machine shop and...Ch. 8 - 13. * More lifting You exert a 630-N force on rope...Ch. 8 - Prob. 14PCh. 8 - 15. * Tightrope walking A tightrope walker wonders...Ch. 8 - 16. * Lifting patients An apparatus to lift...Ch. 8 - 17. A father (80 kg), mother (56 kg), daughter (16...Ch. 8 - Prob. 18PCh. 8 - * You place a 3.0-m-long board symmetrically...Ch. 8 - Prob. 20PCh. 8 - Prob. 21PCh. 8 - Prob. 22PCh. 8 - 23. EST Compare the two different designs of...Ch. 8 - Ray decides to paint the outside of his uncles...Ch. 8 - 25. * A 2.0-m-long uniform beam of mass 8.0 kg...Ch. 8 - * A uniform beam of length / and mass m supports a...Ch. 8 - Prob. 27PCh. 8 - Prob. 28PCh. 8 - Prob. 29PCh. 8 - Prob. 30PCh. 8 - 31. * An 80-kg clown sits on a 20-kg bike on a...Ch. 8 - s center of mass? (Hint: You can think of cutting...Ch. 8 - Leg support A persons broken leg is kept in place...Ch. 8 - Prob. 34PCh. 8 - Prob. 35PCh. 8 - * If the force F shown in Figure P8.35 is 840 N...Ch. 8 - Prob. 37PCh. 8 - 38. * You decide to hang another plant from a...Ch. 8 - Prob. 39PCh. 8 - * What mechanical work must you do to lift a log...Ch. 8 - 41. * A 70-g meter stick has a 30-g piece of...Ch. 8 - * You are trying to tilt a very tall refrigerator...Ch. 8 - Prob. 43PCh. 8 - 44. * You have an Atwood machine (see Figure 4.9 )...Ch. 8 - * EST You stand sideways in a moving train....Ch. 8 - 46. EST Your hand holds a liter of milk (mass...Ch. 8 - EST Body torque You hold a 4.0-kg computer....Ch. 8 - Prob. 48GPCh. 8 - 49. BIO Using triceps to push a table A man pushes...Ch. 8 - Prob. 50GPCh. 8 - Prob. 51GPCh. 8 - Prob. 52GPCh. 8 - 53.* BIO Dumbbell lift IA woman lifts a 3.6-kg...Ch. 8 - s shoulder joint exerts on her humerus.Ch. 8 - Prob. 55GPCh. 8 - * Eiichi has purchased an adjustable hand grip to...Ch. 8 - 57. *BIO While browsing books on neurophysiology,...Ch. 8 - 58. ** Touch detector You have two force sensors...Ch. 8 - * An 80-kg person stands at one end of a 130-kg...Ch. 8 - 61. EST Two people (50 kg and 75 kg) holding hands...Ch. 8 - Prob. 62GPCh. 8 - BIO Muscles work in pairs Skeletal muscles produce...Ch. 8 - BIO Muscles work in pairs Skeletal muscles produce...Ch. 8 - BIO Muscles work in pairs Skeletal muscles produce...Ch. 8 - BIO Muscles work in pairs Skeletal muscles produce...Ch. 8 - BIO Improper lifting and the back A careful study...Ch. 8 - BIO Improper lifting and the back A careful study...Ch. 8 - BIO Improper lifting and the back A careful study...Ch. 8 - BIO Improper lifting and the back A careful study...
Additional Science Textbook Solutions
Find more solutions based on key concepts
A 2.0-kg object has a velocity of at t=0 . A constant resultant force of then acts on the object for 3.0 s. Wha...
University Physics Volume 1
You step onto an initially nonrotating turntable like the one in Fig. 11.8, holding a nonrotating wheel with it...
Essential University Physics: Volume 1 (3rd Edition)
The specific heat capacity of Albertsons Rotini Tricolore is approximately 1.8J/gC. Suppose you toss 340 g of t...
An Introduction to Thermal Physics
74. Is the fact that we see only one side of the Moon evidence that the Moon spins or that it doesn't? Defend y...
Conceptual Physical Science (6th Edition)
8.1 • (a) What is the magnitude of the momentum of a 10,000-kg truck whose speed is 12.0 m/s? (b) What speed wo...
University Physics with Modern Physics (14th Edition)
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
- BIO When a gymnast performing on the rings executes the iron cross, he maintains the position at rest shown in Figure P10.85a. 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 fore Fh on a hand as shown in Figure P10.85b. 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. (b) Suppose an athlete 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 athlete? Figure P10.85arrow_forwardConstruct Your Own Problem Consider a method for measuring the mass of a person's arm in anatomical studies. The subject lies on her back, extends her relaxed arm to the side and two scales are placed below the arm. One is placed under the elbow and the other under the back of her hand. Construct a problem in which you calculate the mass of the arm and find its center of mass based on the scale readings and the distances of the scales from the shoulder joint. You must include a free body diagram of the arm to direct the analysis. Consider changing the position of the scale under the hand to provide more information, if needed. You may wish to consult references to obtain reasonable mass values.arrow_forwardTriceps muscle Biceps m-40 kg m- 25 kg Calculate the force the biceps muscle must exert to hold the forearm and its load as shown in the Figure? * O 480 N.m O None of the answers O 400 N.m O 0.480 kN O 48 Narrow_forward
- A 130-kg horizontal beam is supported at the ends A and B. A 310-kg piano rests a quarter of the way from the end A. Determine the magnitude of the vertical force on the support at A. Express your answer to two significant figures and include the appropriate units. ? FA = Value Units Submit Previous Answers Request Answer X Incorrect; Try Again; 4 attempts remaining Part B Determine the magnitude of the vertical force on the support at B. Express your answer to two significant figures and include the appropriate units. HẢ FB = Value Units %3Darrow_forward! Required information A person who weighs 766 N supports himself on the ball of one foot. The normal force N= 766 N pushes up on the ball of the foot on one side of the ankle joint, while the Achilles tendon pulls up on the foot on the other side of the joint. The center of gravity of the person is located right above the tibia. Gastrocnemius- soleus muscles Tibia FAchilles Tibia Achilles tendon Calcaneus (heel bone) 12.8 cm * 4.60 cm What is the magnitude of the downward force exerted on the ankle joint by the tibia?arrow_forwardQUESTION 3 What does it mean when we say "an object is in equilibrium"? Choose all that apply. O there are no torques acting on the object O there is no friction acting on the object there is no net force acting on the object O the object has no inertia the object has no energy Dthe object has no momentum Dthere is no net torque acting on the object there are no forces acting on the object Chck Sane and Submit to sare and submie Click Save All Anscewo sae all answers ロ000O000arrow_forward
- During the downward portion of a biceps curl the velocity of the dumbbell is held constant. If the dumbbell weighs 50 N what is the internal force produced by the muscles? a. 50 N b. < 50 N c. > 50 N d. need more informationarrow_forward2. For the beam shown: a. Draw the free-body diagram of the beam. 1.8 m 1.8m 1.38 kN b. Determine the reactions at the supports. 0.80 kN 25 "15m 2.1marrow_forwardA 1 530-kg automobile has a wheel base (the distance between the axles) of 2.80 m. The automobile's center of mass is on the centerline at a point 1.25 m behind the front axle. Find the force exerted by the ground on each wheel. each front wheel each rear wheel 3.345 X This is the force that acts on a rear wheel. kN You appear to have correctly calculated this force using your incorrect result from part (a). kNarrow_forward
- The chewing muscle, the masseter, is one of the strongest in the human body. It is attached to the mandible (lower jawbone) as shown in figure (a). The jawbone is pivoted about a socket just in front of the auditory canal. The forces acting on the jawbone are equivalent to those acting on the curved bar in figure (b). 3.50 cm - 7.50 cm Masseter Mandible a Fc is the force exerted by the food being chewed against the jawbone, T is the force of tension in the masseter, and R is the force exerted by the socket on the mandible. Find T and R (in N) for a person who bites down on a piece of steak with a force of 56.6 N. magnitude ofR N magnitude of T Need Help? Read It Watch Itarrow_forwardQ.2) Answer the following questions: a) Why does any person lean towards right while carrying a bag in her left hand?arrow_forwardTEXT ANSWER Question 22 When Jenny couldn't lift a box by herself, she decided to use a lever to move it. She placed a fulcrum 1.6 m away from the box and used a 2.0 m lever to try to lift the box. Her effort was still unsuccessful. Explain why Jenny was unable to lift the box with her lever, and sug- gest a way she can adjust the lever to improve her chances of success. Use math to support your answer.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegeCollege PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
College Physics
Physics
ISBN:9781938168000
Author:Paul Peter Urone, Roger Hinrichs
Publisher:OpenStax College
College Physics
Physics
ISBN:9781305952300
Author:Raymond A. Serway, Chris Vuille
Publisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
What is Torque? | Physics | Extraclass.com; Author: Extraclass Official;https://www.youtube.com/watch?v=zXxrAJld9mo;License: Standard YouTube License, CC-BY