Concept explainers
The Balloon and the Wall When a charged balloon sticks to a wall, the downward gravitational force is balanced by an upward static friction force. The normal force is provided by the electrical attraction between the charged balloon and the equal but oppositely charged polarization induced in the wall’s molecules. If the mass of a balloon is 1.9 g, its coefficient of static friction with the wall is 0.74, and the average distance between the opposite charges is 0.45 mm, what minimum amount of charge must be placed on the balloon in order for it to stick to the wall?
Trending nowThis is a popular solution!
Chapter 19 Solutions
Physics (5th Edition)
Additional Science Textbook Solutions
The Cosmic Perspective (8th Edition)
University Physics (14th Edition)
University Physics Volume 1
Conceptual Integrated Science
College Physics: A Strategic Approach (3rd Edition)
Essential University Physics: Volume 1 (3rd Edition)
- Many textbooks claim Franklin decided that moving charged particles are positive. How would you correct this claim? Think about these questions in developing your answer: Did Franklins model include particles? What did the terms positive and negative mean to Franklin?arrow_forward(a) Two protons in a molecule are 3.80 10-10 m apart. Find the magnitude of the electric force exerted by one proton on the other. (b) State how the magnitude of this force compares with the magnitude of the gravitational force exerted by one proton on the other. (c) What If? What must be a particles charge-to-mass ratio if the magnitude of the gravitational force between two of these particles is equal to the magnitude of electric force between them?arrow_forwardWhy does a car always attract dust right after it is polished? (Note that car wax and car tires are insulators.)arrow_forward
- In 1911, Ernest Rutherford and his assistants Geiger and Marsden conducted an experiment in which they scattered alpha particles (nuclei of helium atoms) from thin sheets of gold. An alpha particle, having charge +2e and mass 6.64 10-27 kg, is a product of certain radioactive decay's. The results of the experiment led Rutherford to the idea that most of an atoms mass is in a very small nucleus, with electrons in orbit around it. (This is the planetary model of the atom, which well study in Chapter 42.) Assume an alpha particle, initially very far from a stationary gold nucleus, is fired with a velocity of 2.00 107 m/s directly toward the nucleus (charge +79e). What is the smallest distance between the alpha particle and the nucleus before the alpha particle reverses direction? Assume the gold nucleus remains stationary.arrow_forwardReview. From a large distance away, a particle of mass 2.00 g and charge 15.0 C is fired at 21.0 m/s straight toward a second particle, originally stationary but free to move, with mass 5.00 g and charge 8.50 C. Both particles are constrained to move only along the x axis. (a) At the instant of' closest approach, both particles will be moving at the same velocity. F'ind this velocity. (b) Find the distance of closest approach. After the interaction, the particles will move far apart again. At this time, find the velocity of (c) the 2.00-g particle and (d) the 5.00-g particle.arrow_forwardThe planetary model of the atom pictures electrons orbiting the atomic nucleus much as planets orbit the Sun. In this model you can view hydrogen, the simplest atom, as having a single electron in a circular orbit 1.061010 m in diameter. (a) If the average speed of the electron in this orbit is known to be 2.20106 m/s, calculate the number of revolutions per second it makes about the nucleus. (b) What is the electron's average velocity?arrow_forward
- A positively charged It'd attracts a small piece of cork. (a) Can we conclude that the cork is negatively charged? (b) The rod repels another small piece of cork. Can we conclude that this piece is positively charged?arrow_forwardCathode ray tubes (CRTs) used in old-style televisions have been replaced by modern LCD and LED screens. Part of the CRT included a set of accelerating plates separated by a distance of about 1.50 cm. If the potential difference across the plates was 25.0 kV, find the magnitude of the electric field in the region between the plates.arrow_forwardIn the Millikan oil-drop experiment illustrated in Figure 15.21, an atomizer (a sprayer with a fine nozzle) is used to introduce many tiny droplets of oil between two oppositely charged parallel metal plates. Some of the droplets pick up one or more excess electrons. The charge on the plates is adjusted so that the electric force on the excess electrons exactly balances the weight of the droplet. The idea is to look for a droplet dial has the smallest electric force and assume it has only one excess electron. This strategy lets the observer measure the charge on the electron. Suppose we are using an electric field of 3 104 N/C. The charge on one electron is about 1.6 1019 C. Estimate the radius of an oil drop of density 858 kg/m5 for which its weight could be balanced by the electric force of this field on one electron. (Problem 42 is courtesy of E.F. Redish. For more problems of this type, visit www.physics.umd.cdu/pcrg/.)arrow_forward
- Why do most objects tend to contain nearly equal numbers of positive and negative charges?arrow_forwardReview. From a large distance away, a particle of mass m1, and positive charge q1 is fired at speed in the positive x direction straight toward a second particle, originally stationary but free to move, with mass m2, and positive charge q2. Both particles are constrained to move only along the x axis. (a) At the instant of closest approach, both particles will be moving at the same velocity. Find this velocity, (b) Find the distance of closest approach. After the interaction, the particles will move far apart again. At this time, find the velocity of (c) the particle of mass m1, and (d) the particle of mass m2.arrow_forwardA charged particle moves through a velocity selector at constant velocity. In tire selector, E=1.0104NC and B = 0.250 T. When the electric field is turned off, tire charged particle travels in a circular path of radius 3.33 mm. Determine the charge-to-mass ratio of the particle.arrow_forward
- College PhysicsPhysicsISBN:9781938168000Author:Paul Peter Urone, Roger HinrichsPublisher:OpenStax CollegePhysics for Scientists and Engineers, Technology ...PhysicsISBN:9781305116399Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
- College PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningGlencoe Physics: Principles and Problems, Student...PhysicsISBN:9780078807213Author:Paul W. ZitzewitzPublisher:Glencoe/McGraw-Hill