Chapter 6: Q8 (page 276)
Show the validity of the relation when , by making these substitutions:
Short Answer
The given equation is verified.
/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none}
Learning Materials
Features
Discover
Chapter 6: Q8 (page 276)
Show the validity of the relation when , by making these substitutions:
The given equation is verified.
All the tools & learning materials you need for study success - in one app.
Get started for free
A pendulum (see Figure ) consists of a very light but stiff rod of length hanging from a nearly frictionless axle, with a mass at the end of the rod.
(a) Calculate the gravitational potential energy as a function of the angle , measured from the vertical.
(b) Sketch the potential energy as a function of the angle , for angles from to .
(c) Let the arc length away from the bottom of the arc. Calculate the tangential component of the force on the mass by taking the (negative) gradient of the energy with respect to . Does your result make sense?
(d) Suppose that you hit the stationary hanging mass so it has an initial speed .
What is the minimum initial speed needed for the pendulum to go over the top ? On your sketch of the potential energy (part b), draw and label energy levels for the case in which the initial speed is less than, equal to, or greater than this critical initial speed.

The point of this question is to compare rest energy and kinetic energy at low speeds. A baseball is moving at a speed of . Its mass is (). (a) What is its rest energy? (b) Is it okay to calculate its kinetic energy using the expressionrole="math" localid="1657713286046" ? (c) What is its kinetic energy? (d) Which is true? A. the kinetic energy is approximately equal to the rest energy. B. the kinetic energy is much bigger than the rest energy. C. the kinetic energy is much smaller than the rest energy.
A comet is in elliptical orbit around the Sun. Its closest approach to the Sun is a distance of (inside the orbit of Mercury), at which point its speed is . Its farthest distance from the Sun is far beyond the orbit of Pluto. What is its speed when it is from the Sun? (This is the approximate distance of Pluto from the Sun.)
You bring a boat toward the dock by pulling on a rope with a force of130 N through a distance of 6 M . (a) How much work do you do? (Include the appropriate sign.) (b) Then you slow the boat down by pushing against it with a force of 40 N, opposite to the boat’s movement of. How much work do you do? (Include the appropriate sign.) (c) What is the total amount of work that you do?
One end of a spring whose spring constant is 20N/mis attached to the wall, and you pull on the other end, stretching it from its equilibrium length of 0.2mto a length of 0.3m. Estimate the work done by dividing the stretching process into two stages and using the average force you exert to calculate work done during each stage.
What do you think about this solution?
We value your feedback to improve our textbook solutions.