Physics for Scientists and Engineers with Modern Physics
4th Edition
ISBN: 9780131495081
Author: Douglas C. Giancoli
Publisher: Addison-Wesley
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Textbook Question
Chapter 11, Problem 12Q
Explain how a child “pumps” on a swing to make it go higher.
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Check out a sample textbook solutionStudents have asked these similar questions
(a) Calculate the force (in N) the woman in the figure below exerts to do a push-up at constant speed, taking all data to be known to three digits. (You may need to use torque methods from a later chapter.)
m = 56 kg
CG
N
0.86 m
1.44 m
W
reaction
(b) How much work (in J) does she do if her center of mass rises 0.200 m?
(c) What is her useful power output (in W) if she does 18 push-ups in 1 min? (Should work done lowering her body be included? See the discussion of useful work in Work, Energy, and Power in Humans.)
W
What energy transformations are involved when a dragster engine is revved, its clutch let out rapidly, its tires spun, and it starts to accelerate forward? Describe the source and transformation of energy at each step.
(a) Calculate the force (in N) the woman in the figure below exerts to do a push-up at constant speed, taking all data to be known to three digits. (You may need to use torque methods from a later
chapter.)
m =
68 kg
CG
Fre
reaction
0.85 m
1.41 m
N
(b) How much work (in J) does she do if her center of mass rises 0.220 m?
(c) What is her useful power output (in W) if she does 15 push-ups in 1 min? (Should work done lowering her body be included? See the discussion of useful work in Work, Energy, and Power in
Humans.)
W
Chapter 11 Solutions
Physics for Scientists and Engineers with Modern Physics
Ch. 11.1 - CONCEPTUAL EXAMPLE 115 Spinning bicycle wheel....Ch. 11.1 - CONCEPTUAL EXAMPLE 115 Spinning bicycle wheel....Ch. 11.1 - Suppose you are standing on the edge of a large...Ch. 11.2 - For the vectors A and B in the plane of the page...Ch. 11.2 - Prob. 1EECh. 11 - If there were a great migration of people toward...Ch. 11 - Can the diver of Fig. 112 do a somersault without...Ch. 11 - Suppose you are sitting on a rotating stool...Ch. 11 - When a motorcyclist leaves the ground on a jump...Ch. 11 - Suppose you are standing on the edge of a large...
Ch. 11 - A shortstop may leap into the air to catch a ball...Ch. 11 - If all the components of the vectors V1 and V2...Ch. 11 - Name the four different conditions that could make...Ch. 11 - A force F=Fj is applied to an object at a position...Ch. 11 - A particle moves with constant speed along a...Ch. 11 - If the net force on a system is zero, is the net...Ch. 11 - Explain how a child pumps on a swing to make it go...Ch. 11 - Describe the torque needed if the person in Fig....Ch. 11 - An astronaut floats freely in a weightless...Ch. 11 - On the basis of the law of conservation of angular...Ch. 11 - A wheel is rotating freely about a vertical axis...Ch. 11 - Consider the following vector quantities:...Ch. 11 - How does a car make a right turn? Where does the...Ch. 11 - The axis of the Earth processes with a period of...Ch. 11 - Why is it that at most locations on the Earth, a...Ch. 11 - In a rotating frame of reference. Newtons first...Ch. 11 - In the battle of the Falkland Islands in 1914, the...Ch. 11 - Wha is the anugular momentum of a 0.210-kg ball...Ch. 11 - (I) (a) What is the angular momentum of a 2.8-kg...Ch. 11 - (II) A person stands, hands at his side, on a...Ch. 11 - (II) A figure skater can increase her spin...Ch. 11 - (II) A diver (such as the one shown in Fig. 112)...Ch. 11 - (II) A uniform horizontal rod of mass M and length...Ch. 11 - (II) Determine the angular momentum of the...Ch. 11 - (II) (a) What is the angular momentum of a figure...Ch. 11 - (II) A person stands on a platform, initially at...Ch. 11 - (II) A uniform disk turns at 3.7 rev/s around a...Ch. 11 - (II) A person of mass 75 kg stands at the center...Ch. 11 - (II) A potters wheel is rotating around a vertical...Ch. 11 - (II) A 4.2-m-diameter merry-go-round is rotating...Ch. 11 - (II) A woman of mass m stands at the edge of a...Ch. 11 - (II) A nonrotating cylindrical disk of moment of...Ch. 11 - (II) Suppose our Sun eventually collapses into a...Ch. 11 - (III) Hurricanes can involve winds in excess of...Ch. 11 - (III) An asteroid of mass 1.0 105 kg, traveling...Ch. 11 - (III) Suppose a 65-kg person stands at the edge of...Ch. 11 - (I) If vector A points along the negative x axis...Ch. 11 - (I) Show that (a) i i = j j = k k = 0. (b) i j...Ch. 11 - (I) The directions of vectors A and B are given...Ch. 11 - (II) What is the angle between two vectorsA and...Ch. 11 - (II) A particle is located at r=(4.0i+3.5j+6.0k)m....Ch. 11 - (II) Consider a particle of a rigid object...Ch. 11 - (II) (a) Show that the cross product of two...Ch. 11 - (II) An engineer estimates that under the most...Ch. 11 - (II) The origin of a coordinate system is at the...Ch. 11 - (II) Use the result of Problem 26 to determine (a)...Ch. 11 - (III) Show that the velocity v of any point in an...Ch. 11 - (III) Let A,B, and Cbe three vectors, which for...Ch. 11 - (I) What are the x, y, and z components of the...Ch. 11 - (I) Show that the kinetic energy K of a particle...Ch. 11 - (I) Calculate the angular momentum of a particle...Ch. 11 - (II) Two identical particles have equal but...Ch. 11 - (II) Determine the angular momentum of a 75-g...Ch. 11 - (II) A particle is at the position (x, y, z) =...Ch. 11 - Prob. 38PCh. 11 - (II) Four identical particles of mass m are...Ch. 11 - (II) Two lightweight rods 24 cm in length are...Ch. 11 - (II) Figure 1135 shows two masses connected by a...Ch. 11 - (III) A thin rod of length and mass M rotates...Ch. 11 - (III) Show that the total angular momentum L=ripi...Ch. 11 - (III) What is the magnitude of the force F exerted...Ch. 11 - Prob. 45PCh. 11 - Prob. 46PCh. 11 - (II) A thin rod of mass M and length is suspended...Ch. 11 - (II) A uniform stick 1.0 m long with a total mass...Ch. 11 - (II) Suppose a 5.8 1010 kg meteorite struck the...Ch. 11 - (III) A 230-kg beam 2.7 m in length slides...Ch. 11 - (III) A thin rod of mass M and length rests on a...Ch. 11 - (III) On a level billiards table a cue ball,...Ch. 11 - (II) A 220-g top spinning at 15 rev/s makes an...Ch. 11 - (II) A toy gyroscope consists of a 170-g disk with...Ch. 11 - Prob. 55PCh. 11 - Prob. 56PCh. 11 - (II) A bicycle wheel of diameter 65 cm and mass m...Ch. 11 - Prob. 58PCh. 11 - Prob. 59PCh. 11 - (II) Suppose the man at B in Fig. 1126 throws the...Ch. 11 - (II) For what directions of velocity would the...Ch. 11 - (III) We can alter Eqs. 1114 and 1115 for use on...Ch. 11 - (III) An ant crawls with constant speed outward...Ch. 11 - A thin string is wrapped around a cylindrical hoop...Ch. 11 - A particle of mass 1.00 kg is moving with velocity...Ch. 11 - A merry-go-round with a moment of inertia equal to...Ch. 11 - Why might tall narrow SUVs and buses be prone to...Ch. 11 - A spherical asteroid with radius r = 123 m and...Ch. 11 - Prob. 69GPCh. 11 - The position of a particle with mass m traveling...Ch. 11 - A boy rolls a tire along a straight level street....Ch. 11 - A 70 kg person stands on a tiny rotating platform...Ch. 11 - Water drives a waterwheel (or turbine) of radius R...Ch. 11 - The Moon orbits the Earth such that the same side...Ch. 11 - A particle of mass m uniformly accelerates as...Ch. 11 - A projectile with mass m is launched from the...Ch. 11 - Most of our Solar Systems mass is contained in the...Ch. 11 - Prob. 78GPCh. 11 - Competitive ice skaters commonly perform single,...Ch. 11 - A radio transmission tower has a mass of 80 kg and...Ch. 11 - Suppose a star the size of our Sun, but with mass...Ch. 11 - A baseball bat has a sweet spot where a ball can...Ch. 11 - (II) A uniform stick 1.00 m long with a total mass...
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