PHY F/SCIENTIST MOD MASTERING 24 MO
17th Edition
ISBN: 9780137319497
Author: Knight
Publisher: PEARSON
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Chapter 12, Problem 82EAP
A 45 kg figure skater is spinning on the toes of her skates at 1.0 rev/s. Her arms are outstretched as far as they will go. In this orientation, the skater can be modeled as a cylindrical torso (40 kg, 20 cm average diameter, 160 cm tall) plus two rod-like arms (2.5 kg each, 66 cm long) attached to the outside of the torso. The skater then raises her arms straight above her head, where she appears to be a 45 kg, 20-cm-diameter, 200-cm-tall cylinder. What is her new
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A 45 kg figure skater is spinning on the toes of her skates at 1.0 rev/s . Her arms are outstretched as far as they will go. In this orientation, the skater can be modeled as a cylindrical torso (40 kg , 20 cm average diameter, 160 cm tall) plus two rod-like arms (2.5 kg each, 70 cm long) attached to the outside of the torso. The skater then raises her arms straight above her head, where she appears to be a 45 kg, 20-cm-diameter, 200-cm-tall cylinder.
What is her new rotation frequency, in revolutions per second?
A 45 kg figure skater is spinning on the toes of her skates at
0.60 rev/s. Her arms are outstretched as far as they will go. In
this orientation, the skater can be modeled as a cylindrical torso
(40 kg, 20 cm average diameter, 160 cm tall) plus two rod-like
arms (2.5 kg each, 61 cm long) attached to the outside of the
torso. The skater then raises her arms straight above her head,
where she appears to be a 45 kg, 20-cm-diameter, 200-cm-tall
cylinder.
Part A
What is her new rotation frequency, in revolutions per second?
Express your answer in revolutions per second to two significant figures.
• View Available Hint(s)
ΑΣφ
?
@2 =
rev/s
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The Bunchberry flower has the fastest moving parts ever observed in a plant. Initially, the
stamens are held by the petals in a bent position, storing elastic energy like a coiled spring. When
the petals release, the tips of the stamen act like medieval catapults, flipping through a 60° angle
in just 0.30 ms.to launch pollen from anther sacs at their ends. The human eye just sees a burst
of pollen; only high speed photography reveals the details. We can model the stamen tip as a
1.0 mm long, 10µg rigid rod with a 10µg anther sac
at the end. Although oversimplifying, we'll assume a
Pollen
Pollen
Anther sac
constant angular acceleration.
A. How large is the "straightening torque"? (you
may assume the torques created by the gravity
1.0 mm
Stamen
force
are
minimal
compared
to
the
straightening torque, and can be ignored.
B. What is the speed of the anther sac as it releases its pollen?
Initial configuration
Final configuration
Chapter 12 Solutions
PHY F/SCIENTIST MOD MASTERING 24 MO
Ch. 12 - Prob. 1CQCh. 12 - If the angular velocity w is held constant, by...Ch. 12 - FIGURE Q12.3 shows three rotating disks, all of...Ch. 12 - 4. Must an object be rotating to have a moment of...Ch. 12 - 5. The moment of inertia of a uniform rod about an...Ch. 12 - 6. You have two solid steel spheres. Sphere 2 has...Ch. 12 - The professor hands you two spheres. They have the...Ch. 12 - Six forces are applied to the door in FIGURE...Ch. 12 - Prob. 9CQCh. 12 - Rank in order, from largest to smallest, the...
Ch. 12 - The solid cylinder and cylindrical shell in FIGURE...Ch. 12 - A diver in the pike position (legs straight, hands...Ch. 12 - Prob. 13CQCh. 12 - A high-speed drill reaches 2000 rpm in 0.50 s. a....Ch. 12 - A skater holds her arms outstretched as she spins...Ch. 12 - A ceiling fan with 80-cm-diameter blades is...Ch. 12 - An 18-cm-long bicycle crank arm, with a pedal at...Ch. 12 - Prob. 5EAPCh. 12 - The three masses shown in FIGURE EX12.6 are...Ch. 12 - The three masses shown in FIGURE EX12.7 are...Ch. 12 - A 100 g ball and a 200 g ball are connected by a...Ch. 12 - A thin, 100 g disk with a diameter of 8.0 cm...Ch. 12 - What is the rotational kinetic energy of the...Ch. 12 - The three200g masses in FIGURE EX12.11 are...Ch. 12 - A drum major twirls a 96-cm-long, 400 g baton...Ch. 12 - The four masses shown in FIGURE EX12.13 are...Ch. 12 - The four masses shown in FIGURE EXI2.13 are...Ch. 12 - The three masses shown in FIGURE EXI2.15 are...Ch. 12 - A 12-cm-diameter CD has a mass of 21 g. What is...Ch. 12 - A 25 kg solid door is 220 cm tall, 91 cm wide....Ch. 12 - Prob. 18EAPCh. 12 - In FIGURE EX12.19, what magnitude force provides...Ch. 12 - The 20-cm-diameter disk in FIGURE EX12.20 can...Ch. 12 - The axle in FIGURE EXI2.21 is half the distance...Ch. 12 - A 4.0-rn-long, 500 kg steel beam extends...Ch. 12 - An athlete at the gym holds a 3.0 kg steel ball in...Ch. 12 - An object’s moment of inertia is 2.0 kg m2. Its...Ch. 12 - An object whose moment of inertia is 4.0 kg m2...Ch. 12 - A 1.0 kg ball and a 2.0 kg ball are connected by a...Ch. 12 - Starting from rest, a 12-cm-diameter compact disk...Ch. 12 - A 4.0 kg, 36-cm-diameter metal disk, initially at...Ch. 12 - The two objects in FIGURE EXI2.29 are balanced on...Ch. 12 - Prob. 30EAPCh. 12 - The 3.0-rn-long, 100 kg rigid beam of FIGURE...Ch. 12 - A 5.0 kg cat and a 2.0 kg bowl of tuna fish are at...Ch. 12 - A car tire is 60cm in diameter. The car is...Ch. 12 - A 500 g, 8.0-cm-diameter can is filled with...Ch. 12 - Prob. 35EAPCh. 12 - A solid sphere of radius R is placed at a height...Ch. 12 - Prob. 37EAPCh. 12 - Evaluate the cross products AB and CD .Ch. 12 - Prob. 39EAPCh. 12 - Force F=10j N is exerted on a particle at 5i+5j m....Ch. 12 - A 1.3 kg ball on the end of a lightweight rod is...Ch. 12 - What are the magnitude and direction of the...Ch. 12 - What is the angular momentum vector of the 2.0 kg,...Ch. 12 - Prob. 44EAPCh. 12 - Prob. 45EAPCh. 12 - A 2.0 kg, 20-cm-diameter turntable rotates at 100...Ch. 12 - Prob. 47EAPCh. 12 - A toy gyroscope has a ring of mass M and radius R...Ch. 12 - Prob. 49EAPCh. 12 - Prob. 50EAPCh. 12 - Determine the moment of inertia about the axis of...Ch. 12 - What is the moment of inertia of a 2.0 kg,...Ch. 12 - Calculate by direct integration the moment of...Ch. 12 - Calculate the moment of inertia of the rectangular...Ch. 12 - a. A disk of mass M and radius R has a hole of...Ch. 12 - Consider a solid cone of radius R, height H, and...Ch. 12 - Prob. 57EAPCh. 12 - A 3.0-m-long ladder, as shown in Figure 12.35....Ch. 12 - In FIGURE P12.59, an 80 kg construction worker...Ch. 12 - Prob. 60EAPCh. 12 - Prob. 61EAPCh. 12 - A 120-cm-wide sign hangs from a 5.0 kg,...Ch. 12 - Prob. 63EAPCh. 12 - Flywheels are large, massive wheels used to store...Ch. 12 - of mass m1and m2are connected by a massless string...Ch. 12 - The 2.0 kg, 30-cm-diameter disk in FIGURE P12.66...Ch. 12 - A 30-cm-diameter, 1.2 kg solid turntable rotates...Ch. 12 - Your engineering team has been assigned the task...Ch. 12 - A hollow sphere is rolling along a horizontal...Ch. 12 - A 750 g disk and a 760 g ring, both 15 cm in...Ch. 12 - A cylinder of radius R, length L. and mass M is...Ch. 12 - The 5.0 kg, 60-cm-diameter disk in FIGURE P12.72...Ch. 12 - A thin, uniform rod of length L and mass M is...Ch. 12 - A long, thin rod of mass M and length L is...Ch. 12 - The marble rolls down the track shown in FIGURE...Ch. 12 - sThe sphere of mass M and radius R in FIGURE...Ch. 12 - A satellite follows the elliptical orbit shown in...Ch. 12 - A 10 g bullet traveling at 400 m/s strikes a 10...Ch. 12 - A 200 g, 40-cm-diameter turntable rotates on...Ch. 12 - Luc, who is 1.80 m tall and weighs 950 N, is...Ch. 12 - A merry-go-round is a common piece of playground...Ch. 12 - A 45 kg figure skater is spinning on the toes of...Ch. 12 - Prob. 83EAPCh. 12 - The earth’s rotation axis, which is tilted 23.5...Ch. 12 - sThe bunchberry flower has the fastest-moving...Ch. 12 - The two blocks in FIGURE CP12.86 are connected by...Ch. 12 - A rod of length L and mass M has a nonuniform mass...Ch. 12 - In FIGURE CP12.88, a 200 g toy car is placed on a...Ch. 12 - Prob. 89EAPCh. 12 - A 75 g, 30-cm-long rod hangs vertically on a...
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Moment of Inertia; Author: Physics with Professor Matt Anderson;https://www.youtube.com/watch?v=ZrGhUTeIlWs;License: Standard Youtube License