VECTOR MECH...,STAT.+DYNA.(LL)-W/ACCESS
VECTOR MECH...,STAT.+DYNA.(LL)-W/ACCESS
11th Edition
ISBN: 9781259633133
Author: BEER
Publisher: MCG
bartleby

Concept explainers

bartleby

Videos

Textbook Question
Book Icon
Chapter 18, Problem 18.147RP

Three 25-lb rotor disks are attached to a shaft that rotates at 720 rpm. Disk A is attached eccentrically so that its mass center is 1 4 in . from the axis of rotation, while disks B and C are attached so that their mass centers coincide with the axis of rotation. Where should 2-lb weights be bolted to disks B and C to balance the system dynamically?

Chapter 18, Problem 18.147RP, Three 25-lb rotor disks are attached to a shaft that rotates at 720 rpm. Disk A is attached

Fig. P18.147

Expert Solution & Answer
Check Mark
To determine

Where should 2 lb weights be bolted to disks B and C to balance the system dynamically.

Answer to Problem 18.147RP

The 2 lb weights be bolted to disks B and C to balance the system dynamically are 614in.(belowshaft)_ and 318in.(aboveshaft)_.

Explanation of Solution

Given Information:

The weight (W) of the disk is 25 lb.

The shaft rotates at 720 rpm.

The mass center of the disk A is 14in.

Calculation:

Draw the free body diagram of the system as shown in Figure (1).

VECTOR MECH...,STAT.+DYNA.(LL)-W/ACCESS, Chapter 18, Problem 18.147RP

The angular velocity of the shaft is constant. So, the rate of change of angular momentum is zero.

Express the effective force (FA) of disk A:

FA=mrAω2j

Here,ω is angular velocity.

Express the effective force (FB) of disk B:

FB=mrBω2j

Express the effective force (FC) of disk C:

FC=mrCω2j

The sum of the effective forces of the discs should be equal to zero for the system to be in dynamic balance.

FA+FB+FC=0

Substitute mrAω2j for FA, mrBω2j for FB, and mrCω2j for FC.

mrAω2j+mrBω2j+mrCω2j=0mrBω2j+mrCω2j=mrAω2jmω2(rB+rC)=mrAω2jrB+rC=mmrA

Substitute 14in. for rA, 25 lb for m, and 2 lb for m.

rB+rC=25lb2lb(14in.)rB+rC=258rB+rC=3.125in. (1)

According to principle of impulse momentum, the total momentum is zero.

Express the moment about O:

a(mrAω2j)+b(mrBω2j)+c(mrCω2j)=0

Here, a is distance between O and A, b is distance between O and B and c distance between O and C .

Substitute 4i for a, 10i for b, and 16i for c.

4i(mrAω2j)+10i(mrBω2j)+16i(mrCω2j)=010i(mrBω2j)+16i(mrCω2j)=4i(mrAω2j)mω2(10rB+16rC)=4(mrAω2)10rB+16rC=4mmrA

Substitute 14in. for rA, 25 lb for m, and 2 lb for m.

10rB+16rC=425lb2lb(14in.)10rB+16rC=12.5in. (2)

Multiply Equation (1) by 10 and add to Equation (2).

10rB10rC+10rB+16rC=12.5in.31.25in.6rC=18.75rC=18.756rC=3.125in.rC=258in.rC=318in.

The 2 lb weight is be placed above the shaft for disk C.

Substitute 3.125in. for rC in Equation (1).

rB3.125in.=3.125in.rB=6.25in.rB=254in.rB=614in.

The 2 lb weight is be placed below the shaft for disk B.

Thus, the 2 lb weights be bolted to disks B and C to balance the system dynamically are 614in.(belowshaft)_ and 318in.(aboveshaft)_.

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
Q1: Determine the length, angle of contact, and width of a 9.75 mm thick leather belt required to transmit 15 kW from a motor running at 900 r.p.m. The diameter of the driving pulley of the motor is 300 mm. The driven pulley runs at 300 r.p.m. and the distance between the centers of two pulleys is 3 meters. The density of the leather is 1000 kg/m³. The maximum allowable stress in the leather is 2.5 MPa. The coefficient of friction between the leather and pulley is 0.3. Assume open belt drive.
5. A 15 kW and 1200 r.p.m. motor drives a compressor at 300 r.p.m. through a pair of spur gears having 20° stub teeth. The centre to centre distance between the shafts is 400 mm. The motor pinion is made of forged steel having an allowable static stress as 210 MPa, while the gear is made of cast steel having allowable static stress as 140 MPa. Assuming that the drive operates 8 to 10 hours per day under light shock conditions, find from the standpoint of strength, 1. Module; 2. Face width and 3. Number of teeth and pitch circle diameter of each gear. Check the gears thus designed from the consideration of wear. The surface endurance limit may be taken as 700 MPa. [Ans. m = 6 mm; b= 60 mm; Tp=24; T=96; Dp = 144mm; DG = 576 mm]
4. G A micarta pinion rotating at 1200 r.p.m. is to transmit 1 kW to a cast iron gear at a speed of 192 r.p.m. Assuming a starting overload of 20% and using 20° full depth involute teeth, determine the module, number of teeth on the pinion and gear and face width. Take allowable static strength for micarta as 40 MPa and for cast iron as 53 MPa. Check the pair in wear.

Chapter 18 Solutions

VECTOR MECH...,STAT.+DYNA.(LL)-W/ACCESS

Ch. 18.1 - Prob. 18.12PCh. 18.1 - Prob. 18.13PCh. 18.1 - Two L-shaped arms each have a mass of 5 kg and are...Ch. 18.1 - For the assembly of Prob. 18.15, determine (a) the...Ch. 18.1 - Prob. 18.17PCh. 18.1 - Determine the angular momentum of the shaft of...Ch. 18.1 - Prob. 18.20PCh. 18.1 - Prob. 18.21PCh. 18.1 - Prob. 18.22PCh. 18.1 - Prob. 18.23PCh. 18.1 - Prob. 18.24PCh. 18.1 - Prob. 18.25PCh. 18.1 - Prob. 18.26PCh. 18.1 - Prob. 18.27PCh. 18.1 - Prob. 18.28PCh. 18.1 - A circular plate of mass m is falling with a...Ch. 18.1 - Prob. 18.30PCh. 18.1 - Prob. 18.31PCh. 18.1 - Determine the impulse exerted on the plate of...Ch. 18.1 - The coordinate axes shown represent the principal...Ch. 18.1 - Prob. 18.34PCh. 18.1 - Prob. 18.37PCh. 18.1 - Prob. 18.38PCh. 18.1 - Prob. 18.39PCh. 18.1 - Prob. 18.40PCh. 18.1 - Prob. 18.41PCh. 18.1 - Prob. 18.42PCh. 18.1 - Prob. 18.43PCh. 18.1 - Determine the kinetic energy of the solid...Ch. 18.1 - Prob. 18.45PCh. 18.1 - Determine the kinetic energy of the disk of Prob....Ch. 18.1 - Determine the kinetic energy of the assembly of...Ch. 18.1 - Determine the kinetic energy of the shaft of Prob....Ch. 18.1 - Prob. 18.49PCh. 18.1 - Prob. 18.50PCh. 18.1 - Determine the kinetic energy lost when edge C of...Ch. 18.1 - Prob. 18.52PCh. 18.1 - Prob. 18.53PCh. 18.1 - Determine the kinetic energy of the space probe of...Ch. 18.2 - Determine the rate of change HG of the angular...Ch. 18.2 - Prob. 18.56PCh. 18.2 - Prob. 18.57PCh. 18.2 - Prob. 18.58PCh. 18.2 - Prob. 18.59PCh. 18.2 - Determine the rate of change HG of the angular...Ch. 18.2 - 18.61 Determine the rate of change of the angular...Ch. 18.2 - Prob. 18.62PCh. 18.2 - Prob. 18.63PCh. 18.2 - Prob. 18.64PCh. 18.2 - A slender, uniform rod AB of mass m and a vertical...Ch. 18.2 - Prob. 18.66PCh. 18.2 - The assembly shown consists of pieces of sheet...Ch. 18.2 - The 8-kg shaft shown has a uniform cross-section....Ch. 18.2 - Prob. 18.69PCh. 18.2 - Prob. 18.70PCh. 18.2 - Prob. 18.71PCh. 18.2 - Knowing that the plate of Prob. 18.66 is initially...Ch. 18.2 - Prob. 18.73PCh. 18.2 - The shaft of Prob. 18.68 is initially at rest ( =...Ch. 18.2 - The assembly shown weighs 12 lb and consists of 4...Ch. 18.2 - Prob. 18.76PCh. 18.2 - Prob. 18.79PCh. 18.2 - Prob. 18.80PCh. 18.2 - Prob. 18.81PCh. 18.2 - Prob. 18.82PCh. 18.2 - The uniform, thin 5-lb disk spins at a constant...Ch. 18.2 - The essential structure of a certain type of...Ch. 18.2 - Prob. 18.85PCh. 18.2 - Prob. 18.86PCh. 18.2 - Prob. 18.87PCh. 18.2 - The 2-lb gear A is constrained to roll on the...Ch. 18.2 - Prob. 18.89PCh. 18.2 - Prob. 18.90PCh. 18.2 - 18.90 and 18.91The slender rod AB is attached by a...Ch. 18.2 - The essential structure of a certain type of...Ch. 18.2 - The 10-oz disk shown spins at the rate 1 = 750...Ch. 18.2 - Prob. 18.94PCh. 18.2 - Prob. 18.95PCh. 18.2 - Two disks each have a mass of 5 kg and a radius of...Ch. 18.2 - Prob. 18.97PCh. 18.2 - Prob. 18.98PCh. 18.2 - A thin disk of mass m = 4 kg rotates with an...Ch. 18.2 - Prob. 18.101PCh. 18.2 - Prob. 18.102PCh. 18.2 - A 2.5-kg homogeneous disk of radius 80 mm rotates...Ch. 18.2 - A 2.5-kg homogeneous disk of radius 80 mm rotates...Ch. 18.2 - For the disk of Prob. 18.99, determine (a) the...Ch. 18.3 - A uniform thin disk with a 6-in. diameter is...Ch. 18.3 - A uniform thin disk with a 6-in. diameter is...Ch. 18.3 - Prob. 18.109PCh. 18.3 - The top shown is supported at the fixed point O...Ch. 18.3 - Prob. 18.111PCh. 18.3 - Prob. 18.112PCh. 18.3 - Prob. 18.113PCh. 18.3 - A homogeneous cone with a height of h = 12 in. and...Ch. 18.3 - Prob. 18.115PCh. 18.3 - Prob. 18.116PCh. 18.3 - Prob. 18.117PCh. 18.3 - Prob. 18.118PCh. 18.3 - Prob. 18.119PCh. 18.3 - Prob. 18.120PCh. 18.3 - Prob. 18.121PCh. 18.3 - Prob. 18.122PCh. 18.3 - Prob. 18.123PCh. 18.3 - A coin is tossed into the air. It is observed to...Ch. 18.3 - Prob. 18.125PCh. 18.3 - Prob. 18.126PCh. 18.3 - Prob. 18.127PCh. 18.3 - Prob. 18.128PCh. 18.3 - Prob. 18.129PCh. 18.3 - Prob. 18.130PCh. 18.3 - Prob. 18.131PCh. 18.3 - Prob. 18.132PCh. 18.3 - Prob. 18.133PCh. 18.3 - Prob. 18.134PCh. 18.3 - Prob. 18.135PCh. 18.3 - A homogeneous disk with a radius of 9 in. is...Ch. 18.3 - The top shown is supported at the fixed point O....Ch. 18.3 - Prob. 18.138PCh. 18.3 - Prob. 18.139PCh. 18.3 - Prob. 18.140PCh. 18.3 - Prob. 18.141PCh. 18.3 - Prob. 18.142PCh. 18.3 - Consider a rigid body of arbitrary shape that is...Ch. 18.3 - Prob. 18.144PCh. 18.3 - Prob. 18.145PCh. 18 - Three 25-lb rotor disks are attached to a shaft...Ch. 18 - Prob. 18.148RPCh. 18 - Prob. 18.149RPCh. 18 - A uniform rod of mass m and length 5a is bent into...Ch. 18 - Prob. 18.151RPCh. 18 - Prob. 18.152RPCh. 18 - Prob. 18.153RPCh. 18 - Prob. 18.154RPCh. 18 - Prob. 18.155RPCh. 18 - The space capsule has no angular velocity when the...Ch. 18 - Prob. 18.157RPCh. 18 - The essential features of the gyrocompass are...
Knowledge Booster
Background pattern image
Mechanical Engineering
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.
Similar questions
SEE MORE QUESTIONS
Recommended textbooks for you
Text book image
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Text book image
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Text book image
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Text book image
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Text book image
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Text book image
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY
Mechanical Design (Machine Design) Clutches, Brakes and Flywheels Intro (S20 ME470 Class 15); Author: Professor Ted Diehl;https://www.youtube.com/watch?v=eMvbePrsT34;License: Standard Youtube License