EBK PHYSICS FOR SCIENTISTS AND ENGINEER
EBK PHYSICS FOR SCIENTISTS AND ENGINEER
6th Edition
ISBN: 9781319321710
Author: Mosca
Publisher: VST
bartleby

Concept explainers

bartleby

Videos

Question
Book Icon
Chapter 9, Problem 38P

(a)

To determine

To Find: The average angular acceleration during 4.5-s spin-up and again during 0.24-s spin- down.

(a)

Expert Solution
Check Mark

Answer to Problem 38P

  αavg1=30rad/s2

  αavg2=1.2×102rad/s2

Explanation of Solution

Given:

Initial angular speed of the fly wheel, ωi=0

Final angular speed of the fly wheel

  ωf=4.5rev/s=(4.5rev/s)×( 2πrad 1rev)=9πrad/s

Time taken to pull the rope, Δt=0.95s

Time taken during spin up, Δtup=4.5s

Time taken during spin down, Δtdown=0.24s

Formula used:

  αavg=ΔωΔtαavg=ωfωiΔt

  αavg = average acceleration

  ωf = final angular velocity

  ωi = initial angular velocity

Calculation:

Average angular acceleration for spin up is:

  αavg1=( 9π0)rad/s0.95sαavg1=29.76rad/s230rad/s2

Average angular acceleration for spin down is:

  αavg2=( 09π)rad/s0.24sαavg2=117.8rad/s21.2×102rad/s2

Conclusion:

Spin down acceleration =1.2×102rad/s2

Spin up acceleration =30rad/s2

(b)

To determine

To find: Maximum angular speed reached by fly wheel.

(b)

Expert Solution
Check Mark

Answer to Problem 38P

  ωmax=28rad/s

Explanation of Solution

Given:

Initial angular speed of the fly wheel, ωi=0

Final angular speed of the fly wheel

  ωf=4.5rev/s=(4.5rev/s)×( 2πrad 1rev)=9πrad/s

Formula used:

  ωmax=ωf

Where,

  ωmax = maximum angular velocity

  ωf = final angular velocity

Calculation:

Substitute the given value in the equation,

  ωmax=ωf=9πrad/s28rad/s

Conclusion:

  ωmax=28rad/s is maximum angular speed reached by fly wheel.

(c)

To determine

To find: The ratio of the number of revolutions made during spin-up to the number made during spin down.

(c)

Expert Solution
Check Mark

Answer to Problem 38P

  ΔθupΔθdown4

Explanation of Solution

Given:

Time taken to pull the rope, Δt=0.95s

Time taken during spin up, Δtup=4.5s

Time taken during spin down, Δtdown=0.24s

Angular speed at spin up =0

Angular speed at spin down, ωmax=28rad/s

Angular acceleration for spin up, αup=30rad/s2

Angular acceleration for spin up, αdown=1.2×102rad/s2

Formula used:

Number of revolutions can be obtained by:

  Δθ=ωt+12αt2

Where,

  θ is the number of revolutions.

  Δt is the time taken.

  ω is the angular speed

  α is angular acceleration

Calculation:

For spin-up revolution:

  Δθup=ωtup+12αuptup2Δθup=0+12×30×0.952Δθup=13.5373.....(1)

For spin down revolution:

  Δθdown=ωtdown+12αdowntdown2Δθdown=(28×0.24)+12×(1.2× 102)(0.24)2Δθdown=6.723.456Δθdown=3.264...(2)

Divide equation (1) by equation (2)

  Δθ upΔθ down=13.53733.264Δθ upΔθ down=4.147Δθ upΔθ down4

Conclusion:

Ratio of the number of revolutions made during spin-up to the number made during spin down is 4 .

Want to see more full solutions like this?

Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!
Students have asked these similar questions
suggest a reason ultrasound cleaning is better than cleaning by hand?
Checkpoint 4 The figure shows four orientations of an electric di- pole in an external electric field. Rank the orienta- tions according to (a) the magnitude of the torque on the dipole and (b) the potential energy of the di- pole, greatest first. (1) (2) E (4)
What is integrated science. What is fractional distillation What is simple distillation

Chapter 9 Solutions

EBK PHYSICS FOR SCIENTISTS AND ENGINEER

Ch. 9 - Prob. 11PCh. 9 - Prob. 12PCh. 9 - Prob. 13PCh. 9 - Prob. 14PCh. 9 - Prob. 15PCh. 9 - Prob. 16PCh. 9 - Prob. 17PCh. 9 - Prob. 18PCh. 9 - Prob. 19PCh. 9 - Prob. 20PCh. 9 - Prob. 21PCh. 9 - Prob. 22PCh. 9 - Prob. 23PCh. 9 - Prob. 24PCh. 9 - Prob. 25PCh. 9 - Prob. 26PCh. 9 - Prob. 27PCh. 9 - Prob. 28PCh. 9 - Prob. 29PCh. 9 - Prob. 30PCh. 9 - Prob. 31PCh. 9 - Prob. 32PCh. 9 - Prob. 33PCh. 9 - Prob. 34PCh. 9 - Prob. 35PCh. 9 - Prob. 36PCh. 9 - Prob. 37PCh. 9 - Prob. 38PCh. 9 - Prob. 39PCh. 9 - Prob. 40PCh. 9 - Prob. 41PCh. 9 - Prob. 42PCh. 9 - Prob. 43PCh. 9 - Prob. 44PCh. 9 - Prob. 45PCh. 9 - Prob. 46PCh. 9 - Prob. 47PCh. 9 - Prob. 48PCh. 9 - Prob. 49PCh. 9 - Prob. 50PCh. 9 - Prob. 51PCh. 9 - Prob. 52PCh. 9 - Prob. 53PCh. 9 - Prob. 54PCh. 9 - Prob. 55PCh. 9 - Prob. 56PCh. 9 - Prob. 57PCh. 9 - Prob. 58PCh. 9 - Prob. 59PCh. 9 - Prob. 60PCh. 9 - Prob. 61PCh. 9 - Prob. 62PCh. 9 - Prob. 63PCh. 9 - Prob. 64PCh. 9 - Prob. 65PCh. 9 - Prob. 66PCh. 9 - Prob. 67PCh. 9 - Prob. 68PCh. 9 - Prob. 69PCh. 9 - Prob. 70PCh. 9 - Prob. 71PCh. 9 - Prob. 72PCh. 9 - Prob. 73PCh. 9 - Prob. 74PCh. 9 - Prob. 75PCh. 9 - Prob. 76PCh. 9 - Prob. 77PCh. 9 - Prob. 78PCh. 9 - Prob. 79PCh. 9 - Prob. 80PCh. 9 - Prob. 81PCh. 9 - Prob. 82PCh. 9 - Prob. 83PCh. 9 - Prob. 84PCh. 9 - Prob. 85PCh. 9 - Prob. 86PCh. 9 - Prob. 87PCh. 9 - Prob. 88PCh. 9 - Prob. 89PCh. 9 - Prob. 90PCh. 9 - Prob. 91PCh. 9 - Prob. 92PCh. 9 - Prob. 93PCh. 9 - Prob. 94PCh. 9 - Prob. 95PCh. 9 - Prob. 96PCh. 9 - Prob. 97PCh. 9 - Prob. 98PCh. 9 - Prob. 99PCh. 9 - Prob. 100PCh. 9 - Prob. 101PCh. 9 - Prob. 102PCh. 9 - Prob. 103PCh. 9 - Prob. 104PCh. 9 - Prob. 105PCh. 9 - Prob. 106PCh. 9 - Prob. 107PCh. 9 - Prob. 108PCh. 9 - Prob. 109PCh. 9 - Prob. 110PCh. 9 - Prob. 111PCh. 9 - Prob. 112PCh. 9 - Prob. 113PCh. 9 - Prob. 114PCh. 9 - Prob. 115PCh. 9 - Prob. 116PCh. 9 - Prob. 117PCh. 9 - Prob. 118PCh. 9 - Prob. 119PCh. 9 - Prob. 120PCh. 9 - Prob. 121PCh. 9 - Prob. 122PCh. 9 - Prob. 123PCh. 9 - Prob. 124PCh. 9 - Prob. 126PCh. 9 - Prob. 127PCh. 9 - Prob. 128PCh. 9 - Prob. 129P
Knowledge Booster
Background pattern image
Physics
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
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Text book image
Physics for Scientists and Engineers: Foundations...
Physics
ISBN:9781133939146
Author:Katz, Debora M.
Publisher:Cengage Learning
Text book image
University Physics Volume 1
Physics
ISBN:9781938168277
Author:William Moebs, Samuel J. Ling, Jeff Sanny
Publisher:OpenStax - Rice University
Rotational Kinematics Physics Problems, Basic Introduction, Equations & Formulas; Author: The Organic Chemistry Tutor;https://www.youtube.com/watch?v=0El-DqrCTZM;License: Standard YouTube License, CC-BY