Concept explainers
July 17, 1981, Kansas City: The newly opened Hyatt Regency is packed with people listening and dancing to a band playing favorites from the 1940s. Many of the people are crowded onto the walkways that hang like bridges across the wide atrium. Suddenly two of the walkways collapse, falling onto the merrymakers on the main floor.
The walkways were suspended one above another on vertical rods and held in place by nuts threaded onto the rods. In the original design, only two long rods were to be used, each extending through all three walkways (Fig. 5-24a). If each walkway and the merrymakers on it have a combined mass of M, what is the total mass supported by the threads and two nuts on (a) the lowest walkway and (b) the highest walkway?
Apparently someone responsible for the actual construction realized that threading nuts on a rod is impossible except at the ends, so the design was changed: Instead, six rods were used, each connecting two walkways (Fig. 5-24b). What now is the total mass supported by the threads and two nuts on (c) the lowest walkway, (d) the upper side of the highest walkway, and (e) the lower side of the highest walkway? It was this design that failed on that tragic night—a simple engineering error.
Figure 5.24 Question 7.
Want to see the full answer?
Check out a sample textbook solutionChapter 5 Solutions
Fundamentals of Physics Extended
Additional Science Textbook Solutions
College Physics: A Strategic Approach (3rd Edition)
Physics: Principles with Applications
Introduction to Electrodynamics
Mathematical Methods in the Physical Sciences
- A student suggests that the force of air resistance FA depends on the relative speed of an object passing through the air v according to FA = kvN, where k is a constant with appropriate units that depends on properties of the air and the size and shape of the object and N is a dimensionless exponent. The student has a hollow ball made of two hemispherical shells that can be connected together and disconnected, along with access to other commonly available materials. Write an experimental procedure that the student could follow to make measurements in order to find the value of N, and explain how a graph of In(FA) vs. In(v) could be used to find the values of k and N.arrow_forwardThe historic Stanley Center for the Arts in Utica, New York is the proud owner of the world’s largest LED chandelier. The chandelier is 35 feet wide, 17 feet tall and has a mass of 2900 kg. It is directly supported by four cables which make an angle of 63° with the horizontal. Determine the tension in the cables.arrow_forwardA 80.0 kg mail bag hangs by a vertical rope 3.5 m long. A postal worker then displaces the bag to a position 2.4 m sideways from its original position, always keeping the rope taut.arrow_forward
- A 0.470 kg wooden block is spun around on a wooden table. The wooden block is being spun around on a 2.00 m long massless wire. The wooden block has air being pushed out behind it causing a thrust force of 3.20 N. The air is being pushed out at 70.0° from the radial line as shown in the figure. If the block is initially at rest and the coefficient of friction is 0.360, what is the tension in the wire after 17.0 revolutions?arrow_forwardA7. Consider a spring-mass system as shown in the diagram, which consists of 1.0 kg block held by three identical springs with force constant k = 100 Nm', as shown in Fig. A7. Fig. A7 (a) Consider the block being displaced by a distance x m to the left. Determine the net force (both magnitude and direction) acting on the block by the springs. (b) The block is then released from rest. Show that the block performs simple harmonic motion, and determine the frequency of oscillation.arrow_forwardIn building a house, carpenters use nails from a large box. The box is suspended from a spring twice during the day to measure the usage of nails. At the beginning of the day, the spring stretches 50 cm. At the end of the day, the spring stretches 30 cm. What fraction or percentage of the nails have been used?arrow_forward
- One end of a light spring with spring constant k₁ is attached to the ceiling. A second light spring is attached to the lower end, with spring constant k₂. An object of mass m is attached to the lower end of the second spring. (a) By how much does the pair of springs stretch? (Use the following as necessary: k₁, k₂, m, and g, the gravitational acceleration.) Xtotal = X Because the springs are light, you can treat them as essentially massless, so the only downward force acting on them is mg. Use |F| = kx to find the amount of stretch, x, for each spring, and then find the sum. (b) What is the effective spring constant of the spring system? (Use the following as necessary: K₁, K₂, m, and g, the gravitational acceleration.) Keff X Use your result from part (a), and recast it into the form |F| = Keff* total Solve for keff. = (c) What If? Two identical light springs with spring constant k3 are now individually hung vertically from the ceiling and attached at each end of a symmetric object,…arrow_forwardA spring (spring1) of initial length L10 and spring constant kl is hanging down the ceiling, with a ball (ball1) of mass m1 attached to the bottom of the spring. Another spring (spring2) of initial length L 20 and spring constant k2 is hanging down from ball1 with another ball (ball2) of mass m2 attached to the bottom of spring2. Use g to denote gravity, t is time, L1 is the position of ball1 minus the ceiling, L2 is the position of ball2 minus ball1, the velocity of ball1 is v1, and the velocity of ball2 is v2. What is the expression of the net force Fnet1 and Fnet2 acted upon ball1 and ball2?arrow_forwardA small box of mass 4.1kg is sitting on a board of mass 1kg and length 1.1m(Figure 1). The board rests on a frictionless horizontal surface. The coefficient of static friction between the board and the box is 0.54. The coefficient of kinetic friction between the board and the box is, as usual, less than 0.54. Throughout the problem, use 9.8m/s^2 for the magnitude of the acceleration due to gravity. In the hints, use Fr for the magnitude of the friction force between the board and the box. Figure esc ! 1 FI m₂ L 2 F2 #3 1 of 1 > 80 F3 E $ 4 888 F4 Part A R Find Fmin, the constant force with the least magnitude that must be applied to the board in order to pull the board out from under the the box (which will then fall off of the opposite end of the board). View Available Hint(s) Fmin = Submit Provide Feedback % [5] ΑΣΦ 5 F5 T 1 MacBook Air 6 F6 Y & 7 www. F7 ? U N 8 00 DII FB 1 ( 9 DD F9 I ) C F10 I 1 P (1 Review I Constants F11 I + Next > F12arrow_forward
- A 28.0-kg block is connected to an empty 2.26-kg bucket by a cord running over a frictionless pulley. The coefficient of static friction between the table and the block is 0.48 and the coefficient of kinetic friction between the table and the block is 0.25. Sand is gradually added to the bucket until the system just begins to move. Ignore the mass of the cord. Calculate the mass of sand added to the bucket. Express your answer to two significant figures and include the appropriate units. m= _______ units Calculate the acceleration of the system. Express your answer to two significant figures and include the appropriate units. a= _________ unitsarrow_forwardAn 80.0 kg mail bag hangs by a vertical rope 3.7 m long. A postal worker then displaces the bag to a position 2.5 meters sideways from its original position, always keeping the rope taut. What horizontal force is necessary to hold the bag in the new position?arrow_forwardStudents are performing an experiment with the setup shown above, where a block of mass M sits on a horizontal table. The coefficient of kinetic friction between the block and the table is μk. The block is connected to a hanging object over a pulley. The pulley has negligible mass and friction. The string connecting the two is very light and does not stretch. The students add mass to the hanging object so that its mass is m, where m < M, and the block-hanging object system is released from rest. The hanging object falls for a distance h, at which point it collides with the ground and comes to rest. The block on the table keeps sliding and travels a total distance d before coming to rest. It does not reach the pulley, and d > h. During this experiment does the angular momentum of the block-hanging object system about an axis through the center of the pulley remain constant? Justify your answer.arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning