Physics for Scientists and Engineers, Volume 1, Chapters 1-22
Physics for Scientists and Engineers, Volume 1, Chapters 1-22
8th Edition
ISBN: 9781439048382
Author: Raymond A. Serway, John W. Jewett
Publisher: Cengage Learning
bartleby

Concept explainers

bartleby

Videos

Textbook Question
Book Icon
Chapter 5, Problem 5.79AP

Two blocks of masses m1 and m2, are placed on a table in contact with each other as discussed in Example 5.7 and shown in Figure 5.13a. The coefficient of kinetic friction between the block of mass m1 and the table is μ1, and that between the block of mass m2 and the table is μ2. A horizontal force of magnitude F is applied to the block of mass m1. We wish to find P, the magnitude of the contact force between the blocks. (a) Draw diagrams showing the forces for each block. (b) What is the net force on the system of two blocks? (c) What is the net force acting on m1? (d) What is the net force acting on m2? (e) Write Newton’s second law in the x direction for each block. (f) Solve the two equations in two unknowns for the acceleration a of the blocks in terms of the masses, the applied force F, the coefficients of friction, and g. (g) Find the magnitude P of the contact force between the blocks in terms of the same quantities.

Chapter 5, Problem 5.79AP, Two blocks of masses m1 and m2, are placed on a table in contact with each other as discussed in

(a)

Expert Solution
Check Mark
To determine

The free body diagram of each block with forces.

The free body diagram of an object represents the direction and magnitude of forces acting on the body.

Explanation of Solution

The mass of block 1 is m1, the mass of block 2 is m2, the coefficient of kinetic friction between m1 and the table is μ1, the coefficient of kinetic friction between m2 and the table is μ2 and the magnitude of horizontal force is F.

The free body diagram of the book is given below.

Physics for Scientists and Engineers, Volume 1, Chapters 1-22, Chapter 5, Problem 5.79AP

Figure (1)

The sum of all vertical forces is zero because the block moves on a horizontal surface. So the vertical acceleration, ay=0.

Write the net force in the y-direction for mass m1 using Newton’s law

    F1y=m1aym1g+n1=0n1=m1g

Here, F1y is the vertical force of block 1, ay is the acceleration in the y-direction, n1 is the normal force of block 1 and g is the acceleration due to gravity.

Write the net force in the y-direction for mass m2 using Newton’s law

    F2y=m2aym2g+n2=0n2=m2g

Here, F2y is the vertical force of block 2 and n2 is the normal force of block 2.

Write the equation for kinetic friction for block 1

    f1=μ1n1=μ1m1g

Here, f1 is the frictional force due to mass m1.

Write the equation for kinetic friction for block 2

    f2=μ2n2=μ2m2g

Here, f2 is the frictional force due to mass m2.

In the figure, P is the contact force that arises due to the contact between m1 and m2.

Conclusion:

Therefore, the free body diagram of each block to show the forces is given in figure I.

(b)

Expert Solution
Check Mark
To determine

The net force on the system of two blocks.

Answer to Problem 5.79AP

The net force on the system of two blocks is the external force applied minus the frictional force.

Explanation of Solution

Write the expression for the net force in x-direction for the system of two blocks from the figure I,

  F=Ff1f2+PP=Ff1f2

Here, F is the net force on the system of two blocks.

Conclusion:

Therefore, the net force on the system of two blocks is the external force applied minus the frictional force.

(c)

Expert Solution
Check Mark
To determine

The net force acting on m1.

Answer to Problem 5.79AP

The net force acting on m1 is Ff1P.

Explanation of Solution

Write the expression for the net force in x-direction for the system of two blocks from the figure I,

  F1x=Ff1P

Here, F1x is the net force on the block of mass m1 .

Conclusion:

Therefore, the net force acting on m1 is Ff1P.

(d)

Expert Solution
Check Mark
To determine

The net force acting on m2.

Answer to Problem 5.79AP

The net force acting on m2 is Pf2.

Explanation of Solution

Write the expression for the net force in x-direction for the system of two blocks from the figure I,

  F2x=f2+P=Pf2

Here, F2x is the net force on the block of mass m2 .

Conclusion:

Therefore, the net force acting on m2 is Pf2.

(e)

Expert Solution
Check Mark
To determine

The Newton’s second law in the x direction for each block.

Answer to Problem 5.79AP

The Newton’s second law in the x direction, for m1 is FP=m1a and for m2 is P=m2a.

Explanation of Solution

The block has on a horizontal acceleration ax=a.

Write the Newton’s second law for block 1

  F1x=m1ax

Substitute Ff1P for F1x in the above equation

  Ff1P=m1a

Substitute μ1m1g for f1 in the above equation

    Fμ1m1gP=m1a

Write the Newton’s second law for block 2

  F2x=m2ax

Substitute Pf2 for F2x in the above equation

  Pf2=m2a

Substitute μ2m2g for f2 in the above equation

    Pμ2m2g=m2a

Conclusion:

Therefore, the Newton’s second law in the x direction, for m1 is Fμ1m1gP=m1a and for m2 is Pμ2m2g=m2a.

(f)

Expert Solution
Check Mark
To determine

The acceleration of the blocks.

Answer to Problem 5.79AP

The acceleration of the blocks is (Fμ1m1gμ2m2gm1+m2).

Explanation of Solution

Write the Newton’s second law is for block 1

    FPμ1m1g=m1a                                                              (I)

Write the Newton’s second law is for block 2

    Pμ2m2g=m2a                                                                 (II)

Conclusion:

Add the equation (I) and equation (II) and solve for a.

    FPμ1m1g+Pμ2m2g=m1a+m2aa=(Fμ1m1gμ2m2gm1+m2)

Therefore, the acceleration of the blocks is (Fμ1m1gμ2m2gm1+m2).

(g)

Expert Solution
Check Mark
To determine

The magnitude of the contact force between the blocks in terms of acceleration, mass, applied force and the friction coefficient.

Answer to Problem 5.79AP

The magnitude P of the contact force between the blocks is (m2m1+m2)(F+(μ2μ1)m1g).

Explanation of Solution

Recall the equation (II).

    Pμ2m2g=m2aP=μ2m2g+m2a

Substitute (Fμ1m1gμ2m2gm1+m2) for a in above expression.

    P=μ2m2g+m2(Fμ1m1gμ2m2gm1+m2)=(m2m1+m2)(F+(μ2μ1)m1g)

Conclusion:

Therefore, the magnitude P of the contact force between the blocks is (m2m1+m2)(F+(μ2μ1)m1g).

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
An object of mass m has these three forces acting on it . F1, F2, and F3 are shown in the figure. Assume the x-direction is to the right, and the y-direction is straight upwards. Let F1 = 7 N, F2 = 9 N, and F3 = 2 N. What is the direction of the net force, expressed as the angle θ, in degrees, that the net force vector makes with respect to the +x-axis? Enter an angle between −180∘ and +180∘.
Two crates connected by a rope lie on a horizontal surface (Figure 1). Crate A has mass mA and crate B has mass mB. The coefficient of kinetic friction between each crate and the surface is μk. The crates are pulled to the right at constant velocity by a horizontal force F. In terms of mA, mB, and μk, calculate the magnitude of the force F. Express your answer in terms of some or all of the variables mA, mB, μk, and acceleration due to gravity g. In terms of mA, mB, and μk, calculate the tension in the rope connecting the blocks. Include the free-body diagram or diagrams you used to determine each answer.
As shown on the right, a box is at rest on an incline plane. The mass of the box is 9.59 kg. The plane is inclined by an angle 0 = 53.3°. The coefficient of static friction between the box and the plane is µ = 0.765, while the coefficient of kinetic friction is µ = 0.438 . The force P = 98.6 N is acting up the plane as shown. What is the magnitude of the static friction force acting on the block helping to keep the mass at rest on the plane? m 0

Chapter 5 Solutions

Physics for Scientists and Engineers, Volume 1, Chapters 1-22

Ch. 5 - The driver of a speeding truck slams on the brakes...Ch. 5 - An experiment is performed on a puck on a level...Ch. 5 - The manager of a department store is pushing...Ch. 5 - Two objects are connected by a siring that passes...Ch. 5 - An object of mass m is sliding with speed v, at...Ch. 5 - A truck loaded with sand accelerates along a...Ch. 5 - A large crate of mass m is place on the flatbed of...Ch. 5 - If an object is in equilibrium, which of the...Ch. 5 - A crate remains stationary after it has been...Ch. 5 - An object of mass m moves with acceleration a down...Ch. 5 - If you hold a horizontal metal bar several...Ch. 5 - Your hands are wet, and the restroom towel...Ch. 5 - In the motion picture It Happened One Night...Ch. 5 - If a car is traveling due westward with a constant...Ch. 5 - A passenger sitting in the rear of a bus claims...Ch. 5 - A child tosses a ball straight up. She says that...Ch. 5 - A person holds a ball in her hand, (a) Identify...Ch. 5 - A spherical rubber balloon inflated with air is...Ch. 5 - A rubber ball is dropped onto the floor. What...Ch. 5 - Twenty people participate in a tug-of-war. The two...Ch. 5 - Can an object exert a force on itself? Argue for...Ch. 5 - When you push on a box with a 200-N force instead...Ch. 5 - A weight lifter stands on a bathroom scale. He...Ch. 5 - An athlete grips a light rope that passes over a...Ch. 5 - Suppose you are driving a classic car. Why should...Ch. 5 - In Figure CQ5.16, the light, taut, unstretchable...Ch. 5 - Describe two examples in which the force of...Ch. 5 - The mayor of a city reprimands some city employees...Ch. 5 - Give reasons for the answers to each of the...Ch. 5 - Balancing carefully, three boys inch out onto a...Ch. 5 - Identity action-reaction pairs in the following...Ch. 5 - As shown in Figure CQ5.22, student A, a 55-kg...Ch. 5 - Prob. 5.23CQCh. 5 - A certain orthodontist uses a wire brace to align...Ch. 5 - If a man weighs 900 N on the Earth, what would he...Ch. 5 - A 3.00-kg object undergoes an acceleration given...Ch. 5 - A certain orthodontist uses a wire brace to align...Ch. 5 - A toy rocket engine is securely fastened to a...Ch. 5 - The average speed of a nitrogen molecule in air is...Ch. 5 - The distinction between mass and weight was...Ch. 5 - (a) A cat with a mass of 850 kg in moving to the...Ch. 5 - Review. The gravitational force exerted on a...Ch. 5 - Review. The gravitational force exerted on a...Ch. 5 - Review. An electron of mass 9. 11 1031 kg has an...Ch. 5 - Besides the gravitational force, a 2.80-kg object...Ch. 5 - One or more external forces, large enough to be...Ch. 5 - A brick of mass M has been placed on a rubber...Ch. 5 - Two forces, F1=(6.00i4.00j)N and...Ch. 5 - The force exerted by the wind on the sails of a...Ch. 5 - An object of mass m is dropped al t = 0 from the...Ch. 5 - A force F applied to an object of mass m1,...Ch. 5 - Two forces F1 and F2 act on a 5.00-kg object....Ch. 5 - You stand on the seat of a chair and then hop off....Ch. 5 - A 15.0-lb block rests on the floor. (a) What force...Ch. 5 - Review. Three forces acting on an object are given...Ch. 5 - A 1 00-kg car is pulling a 300-kg trailer....Ch. 5 - If a single constant force acts on an object that...Ch. 5 - Review. Figure P5.15 shows a worker poling a boata...Ch. 5 - An iron bolt of mass 65.0 g hangs from a string...Ch. 5 - Figure P5.27 shows the horizontal forces acting on...Ch. 5 - The systems shown in Figure P5.28 are in...Ch. 5 - Assume the three blocks portrayed in Figure P5.29...Ch. 5 - A block slides down a frictionless plane having an...Ch. 5 - The distance between two telephone poles is 50.0...Ch. 5 - A 3.00-kg object is moving in a plane, with its x...Ch. 5 - A bag of cement weighing 325 N hangs in...Ch. 5 - A bag of cement whose weight is Fg hangs in...Ch. 5 - Two people pull as hard as they can on horizontal...Ch. 5 - Figure P5.36 shows loads hanging from the ceiling...Ch. 5 - An object of mass m = 1.00 kg is observed to have...Ch. 5 - A setup similar to the one shown in Figure P5.38...Ch. 5 - A simple accelerometer is constructed inside a car...Ch. 5 - An object of mass m1 = 5.00 kg placed on a...Ch. 5 - Figure P5.41 shows the speed of a persons body as...Ch. 5 - Two objects are connected by a light string that...Ch. 5 - Two blocks, each of mass m = 3.50 kg, are hung...Ch. 5 - Two blocks, each of mass m, are hung from the...Ch. 5 - In the system shown in Figure P5.23, a horizontal...Ch. 5 - An object of mass m1 hangs from a string that...Ch. 5 - A block is given an initial velocity of 5.00 m/s...Ch. 5 - A car is stuck in the mud. A tow truck pulls on...Ch. 5 - Two blocks of mass 3.50 kg and 8.00 kg arc...Ch. 5 - In the Atwood machine discussed in Example 5.9 and...Ch. 5 - In Example 5.8, we investigated the apparent...Ch. 5 - Consider a large truck carrying a heavy load, such...Ch. 5 - Review. A rifle bullet with a mass of 12.0 g...Ch. 5 - Review. A car is traveling at 50.0 mi/h on a...Ch. 5 - A 25.0-kg block is initially at rest oil a...Ch. 5 - Why is the following situation impassible? Your...Ch. 5 - To determine the coefficients of friction between...Ch. 5 - Before 1960m people believed that the maximum...Ch. 5 - To meet a U.S. Postal Service requirement,...Ch. 5 - A woman at an airport is towing her 20.0-kg...Ch. 5 - Review. A 3.00-kg block starts from rest at the...Ch. 5 - The person in Figure P5.30 weighs 170 lb. As seen...Ch. 5 - A 9.00-kg hanging object is connected by a light,...Ch. 5 - Three objects are connected on a table as shown in...Ch. 5 - Two blocks connected by a rope of negligible mass...Ch. 5 - A block of mass 3.00 kg is pushed up against a...Ch. 5 - Review. One side of the roof of a house slopes up...Ch. 5 - Review. A Chinook salmon can swim underwater at...Ch. 5 - Review. A magician pulls a tablecloth from under a...Ch. 5 - A 5.00-kg block is placed on top of a 10.0-kg...Ch. 5 - The system shown in Figure P5.49 has an...Ch. 5 - A black aluminum glider floats on a film of air...Ch. 5 - A young woman buys an inexpensive used car stock...Ch. 5 - Why is the following situation impossible? A book...Ch. 5 - Review. A hockey puck struck by a hockey stick is...Ch. 5 - A 1.00-kg glider on a horizontal air track is...Ch. 5 - A frictionless plane is 10.0 m long and inclined...Ch. 5 - A rope with mass mr is attached to a block with...Ch. 5 - Two blocks of masses m1 and m2, are placed on a...Ch. 5 - On a single, light, vertical cable that does not...Ch. 5 - An inventive child named Nick wants to reach an...Ch. 5 - In the situation described in Problem 41 and...Ch. 5 - In Example 5.7, we pushed on two blocks on a...Ch. 5 - Prob. 5.84APCh. 5 - An object of mass M is held in place by an applied...Ch. 5 - Prob. 5.86APCh. 5 - Objects with masses m, = 10.0 kg and nut = 5.00 kg...Ch. 5 - Consider the three connected objects shown in...Ch. 5 - A crate of weight Fg is pushed by a force P on a...Ch. 5 - A student is asked to measure the acceleration of...Ch. 5 - A flat cushion of mass m is released from rest at...Ch. 5 - In Figure P5.46, the pulleys and pulleys the cord...Ch. 5 - What horizontal force must be applied to a large...Ch. 5 - An 8.40-kg object slides down a fixed,...Ch. 5 - A car accelerates down a hill (Fig. P5.95), going...Ch. 5 - A time-dependent force, F = (8.00i - 4.00/j),...Ch. 5 - The board sandwiched between two other boards in...Ch. 5 - Initially, the system of objects shown in Figure...Ch. 5 - A block of mass 2.20 kg is accelerated across a...Ch. 5 - Why is the following situation impossible? A...Ch. 5 - Review. A block of mass m = 2.00 kg is released...Ch. 5 - In Figure P5.55, the incline has mass M and is...Ch. 5 - A block of mass m = 2.00 kg rests on the left edge...Ch. 5 - A mobile is formed by supporting four metal...
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
College Physics
Physics
ISBN:9781305952300
Author:Raymond A. Serway, Chris Vuille
Publisher:Cengage Learning
Text book image
University Physics (14th Edition)
Physics
ISBN:9780133969290
Author:Hugh D. Young, Roger A. Freedman
Publisher:PEARSON
Text book image
Introduction To Quantum Mechanics
Physics
ISBN:9781107189638
Author:Griffiths, David J., Schroeter, Darrell F.
Publisher:Cambridge University Press
Text book image
Physics for Scientists and Engineers
Physics
ISBN:9781337553278
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning
Text book image
Lecture- Tutorials for Introductory Astronomy
Physics
ISBN:9780321820464
Author:Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina Brissenden
Publisher:Addison-Wesley
Text book image
College Physics: A Strategic Approach (4th Editio...
Physics
ISBN:9780134609034
Author:Randall D. Knight (Professor Emeritus), Brian Jones, Stuart Field
Publisher:PEARSON
Electric Fields: Crash Course Physics #26; Author: CrashCourse;https://www.youtube.com/watch?v=mdulzEfQXDE;License: Standard YouTube License, CC-BY