
Concept explainers
For Exercises I through 5:
a. Draw an interaction diagram.
b. Identify the "system" on your interaction diagram.
c. Draw a free-body diagram for each object in the system. Use dashed lines to connect members of an action/reaction pair.
1. A soccer ball and a bowling ball have a head-on collision at this instant. Rolling friction is negligible.
2. A weightlifter stands up at constant speed from a squatting position while holding a heavy barbell across his shoulders.
3. A steel cable with mass is lifting a girder. The girder is speeding up.
4. Block A in FIGURE EX7.4 is heavier than block B and is sliding down the incline. All surfaces have friction. The rope is massless, and the massless pulley turns on frictionless bearings. The rope and the pulley are among the interacting objects, but you'll have to decide if they're part of the system.
FIGURE EX7.4 and FIGURE EX7.5
5. Block A in FIGURE EX7.5 is sliding down the incline. The rope is massless, and the massless pulley turns on frictionless bearings, but the surface is not frictionless. The rope and the pulley are among the interacting objects, but you'll have to decide if they're part of the system.

Want to see the full answer?
Check out a sample textbook solution
Chapter 7 Solutions
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)
- Three objects with masses m₁ = 3.8 kg, m₂ = 12 kg, and m 19 kg, respectively, are attached by strings over frictionless pulleys as indicated in the figure below. The horizontal surface exerts a force of friction of 30 N on m2. If the system is released from rest, use energy concepts to find the speed of m¸ after it moves down 4.0 m. m/s m m2 mgarrow_forwardIn order for Jane to return to base camp, she needs to swing across a river of width D that is filled with alligators. She must swing into a wind exerting constant horizontal force F, F = 110 N, L = 40.0 m, 0 = 50.0°, and her mass to be 50.0 kg. Wind →F Tarzan! Jane (a) with what minimum speed (in m/s) must Jane begin her swing to just make it to the other side? (If Jane can make it across with zero initial velocity, enter 0.) m/s on a vine having length L and initially making an angle with the vertical (see below figure). Take D = 48.0 m, (b) Shortly after Jane's arrival, Tarzan and Jane decide to swing back across the river (simultaneously). With what minimum speed (in m/s) must they begin their swing? Assume that Tarzan has a mass of 80.0 kg. m/sarrow_forwardR=2.00 12V 2.00 4.00 4.002 What is the current in one of the 4.0 Q resistors? An isolated point charge q is located at point X. Two other points Y and Z are such that YZ2 XY. Y X What is (electric field at Y)/(electric field at Z)?arrow_forward
- Two objects (m₁ = 4.75 kg and m₂ 2.80 kg) are connected by a light string passing over a light, frictionless pulley as in the figure below. The 4.75-kg object is released from rest at a point h = 4.00 m above the table mg m (a) Determine the speed of each object when the two pass each other. m/s (b) Determine the speed of each object at the moment the 4.75-kg object hits the table. m/s (c) How much higher does the 2.80-kg object travel after the 4.75-kg object hits the table? marrow_forwardA cell of negligible internal resistance is connected to three identical resistors. The current in the cell is 3.0 A. The resistors are now arranged in series. What is the new current in the cell?arrow_forwardA negatively charged sphere is falling through a magnetic field. north pole of magnet direction of motion south pole of magnet What is the direction of the magnetic force acting on the sphere?arrow_forward
- Electrons in a conductor are moving down the page. A proton outside the wire is moving to the right. What is the direction of the magnetic force acting on the proton?arrow_forwardWhat is the resistance of an ideal voltmeter and the resistance of an ideal ammeter? Resistance of an ideal voltmeter Resistance of an ideal ammeter infinite A. zero B. zero zero C. infinite infinite D. infinite zeroarrow_forwardvariable resistor with a resistance range of 0 to 6.0 KQ is connected in series with two resistors of fixed value 6.0 KQ. The cell in the circuit has an emf of 18 V and a negligible internal resistance. 18 V X Y 6.0 ΚΩ 6.0 ΚΩ 0 - 6.0 ΚΩ What is the maximum range of potential difference that can be observed between X and Y?arrow_forward
- A positive point charge of magnitude 1.0 μC and a point charge q are separated by a distance d. electron 1.0 με An electron is placed at a distance d from the +1.0 μC charge. The electric force on the electron is zero. What is q?arrow_forwardTwo point charges of +4q and -q are placed a fixed distance apart. Where is the electric field strength equal to zero? B. +49 D. A network of three resistors is connected to a cell of emf 12V and internal resistance R of 2.0 Q as shown.arrow_forwardThree point charges of equal magnitude are placed at the vertices of an equilateral triangle. The signs of the charges are shown. Point P is equidistant from the vertices of the triangle. What is the direction of the resultant electric field at P? B.arrow_forward
- University Physics Volume 1PhysicsISBN:9781938168277Author:William Moebs, Samuel J. Ling, Jeff SannyPublisher:OpenStax - Rice UniversityPrinciples of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage LearningCollege PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning





