Concept explainers
What can you say about the velocity of a moving body that in dynamic equilibrium? Draw a sketch of such a body using clearly labeled arrows to represent all external forces on the body.

The velocity of a moving body that is dynamic equilibrium and sketch a diagram of such a body.
Answer to Problem 1CQ
The velocity of a body in dynamic equilibrium is a constant, both in magnitude and direction.
Explanation of Solution
Introduction:
A body is said to be in equilibrium if the total force on the body is zero. On this basis, there are two kinds of equilibria- static equilibrium and dynamic equilibrium. According to Newton's first law, a body continues to be in the state of rest or in the state of uniform motion in a straight line, unless acted upon by an external unbalanced force. Further, Newton's second law implies that an unbalanced force produces an acceleration.
The sum of the forces acting on a body which is in dynamic equilibrium is zero. Therefore, the body experiences no acceleration. As a result, its velocity does not change. Thus, the body which is in dynamic equilibrium moves with a constant velocity.
Consider a block of weight W, acted upon by a force F. The block is placed on a horizontal surface. The surface exerts an upward force FNcalled the normal force on the block. A force of friction f acts between the surface and the block. The block moves towards the right with a velocity v.
The forces W and FNare equal and opposite. Thus, the sum of the forces along the vertical direction is zero. If the applied force F and the force of friction f have equal magnitudes but they are directed opposite to each other. Thus, the net force along the horizontal is also equal to zero. The sum of the forces acting on the block, being zero, the block is not accelerated. Thus, the velocity of the block remains constant. It continues to move with the same speed v and in the same direction.
A diagram representing the forces is shown below.
Conclusion:
A moving body under dynamic equilibrium moves with a constant velocity.
Want to see more full solutions like this?
Chapter 9 Solutions
College Physics for AP Courses
Additional Science Textbook Solutions
Biology: Life on Earth with Physiology (11th Edition)
Applications and Investigations in Earth Science (9th Edition)
Human Anatomy & Physiology (2nd Edition)
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
Campbell Essential Biology (7th Edition)
College Physics: A Strategic Approach (3rd Edition)
- Two complex values are z1=8 + 8i, z2=15 + 7 i. z1∗ and z2∗ are the complex conjugate values. Any complex value can be expessed in the form of a+bi=reiθ. Find r and θ for (z1-z∗2)/z1+z2∗. Find r and θ for (z1−z2∗)z1z2∗ Please show all stepsarrow_forwardAn electromagnetic wave is traveling through vacuum in the positive x direction. Its electric field vector is given by E=E0sin(kx−ωt)j^,where j^ is the unit vector in the y direction. If B0 is the amplitude of the magnetic field vector, find the complete expression for the magnetic field vector B→ of the wave. What is the Poynting vector S(x,t), that is, the power per unit area associated with the electromagnetic wave described in the problem introduction? Give your answer in terms of some or all of the variables E0, B0, k, x, ω, t, and μ0. Specify the direction of the Poynting vector using the unit vectors i^, j^, and k^ as appropriate. Please explain all stepsarrow_forwardAnother worker is performing a task with an RWL of only 9 kg and is lifting 18 kg, giving him an LI of 2.0 (high risk). Questions:What is the primary issue according to NIOSH?Name two factors of the RWL that could be improved to reduce risk.If the horizontal distance is reduced from 50 cm to 30 cm, how does the HM change and what effect would it have?arrow_forward
- Two complex values are z1=8 + 8i, z2=15 + 7 i. z1∗ and z2∗ are the complex conjugate values. Any complex value can be expessed in the form of a+bi=reiθ. Find r and θ for z1z2∗. Find r and θ for z1/z2∗? Find r and θ for (z1−z2)∗/z1+z2∗. Find r and θ for (z1−z2)∗/z1z2∗ Please explain all steps, Thank youarrow_forwardAn ac series circuit consists of a voltage source of frequency 60 Hz and voltage amplitude V, a 505-Ω resistor, and a capacitor of capacitance 7.2 μF. What must be the source voltage amplitude V for the average electrical power consumed in the resistor to be 236 W? There is no inductance in the circuit.arrow_forwardAn L−R−C series circuit has R= 280 Ω . At the frequency of the source, the inductor has reactance XLL= 905 Ω and the capacitor has reactance XC= 485 Ω . The amplitude of the voltage across the inductor is 445 V . What is the amplitude of the voltage across the resistor and the capacitor? What is the voltage amplitude of the source? What is the rate at which the source is delivering electrical energy to the circuit?arrow_forward
- A 0.185 H inductor is connected in series with a 98.5 Ω resistor and an ac source. The voltage across the inductor is vL=−(12.5V)sin[(476rad/s)t]vL. Derive an expression for the voltage vR across the resistor. Express your answer in terms of the variables L, R, VL (amplitude of the voltage across the inductor), ω, and t. What is vR at 2.13 ms ? Please explain all stepsarrow_forwardA worker lifts a box under the following conditions:Horizontal distance (H): 30 cmInitial height (V): 60 cmVertical travel (D): 50 cmTorso rotation (A): 30°Frequency: 3 times/minute for 1 hourGrip: Good Question:What is the RWL for this task?What does this value mean in terms of occupational safety?arrow_forwardCan someone helparrow_forward
- Can someone help mearrow_forward3. Four identical small masses are connected in a flat perfect square. Rank the relative rotational inertias (IA, IB, IC) about the three axes of rotation shown. Axes A and B are in the plane of the square, and axis C is perpendicular to the plane, through mass m1. ΙΑ IB m2 m1 m3 Ic m4 (a) IAarrow_forwardConsider the circuit shown in the figure below. (Assume L = 5.20 m and R2 = 440 Ω.) (a) When the switch is in position a, for what value of R1 will the circuit have a time constant of 15.4 µs? (b) What is the current in the inductor at the instant the switch is thrown to position b?arrow_forwardarrow_back_iosSEE MORE QUESTIONSarrow_forward_ios
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningGlencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-HillCollege PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax College
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning





