The cable cars in San Francisco are pulled along their tracks by an underground steel cable that moves along at 9.5 mph. The cable is driven by large motors at a central power station and extends, via an intricate pulley arrangement, for several miles beneath the city streets. The length of a cable stretches by up to 100 ft during its lifetime. To keep the tension FIGURE EX7.21 constant, the cable passes around a 1.5-m-diameter "tensioning pulley" that rolls back and forth on rails, as shown in FIGURE EX7.21. A 2000 kg block is attached to the tensioning pulley's cart, via a rope and pulley, and is suspended in a deep hole. What is the tension in the cable car's cable?
FIGURE EX7.21
Want to see the full answer?
Check out a sample textbook solutionChapter 7 Solutions
Student Workbook for Physics for Scientists and Engineers: A Strategic Approach, Vol 1. (Chs 1-21)
- The distance between two telephone poles is d = 54.0 m. When a 1.20 kg bird lands on the telephone wire midway between the poles, the wire sags h = 0.206 m. How much tension (in N) does the bird produce in the wire? Ignore the weight of the wirearrow_forwardA 6.00 kg box sits at rest at the bottom of a ramp that is 8.00 mm long and is inclined at 30.0 degrees above the horizontal. The coefficient of kinetic friction is μk = 0.40, and the coefficient of static friction is μs = 0.43. What constant force F, applied parallel to the surface of the ramp, is required to push the box to the top of the ramp in a time of 6.00 s? Express your answer to four significant figures and include the appropriate units.arrow_forwardA race car travels 76 m/s around a circulartrack of radius 159 m What is the magnitude of the resultantforce on the 1600 kg driver and his car ifthe car does not slip?Answer in units of kN.arrow_forward
- Three cables are used to tie the balloon shown in Figure. Determine the magnitude of the vertical force (P) exerted by the balloon at A, knowing that the tension in cable AD is 1.099 N. y1 = 4.3 m y2 = 2.2 m x1 = 4.4 m x2 = 3.1 m z = 5.8 marrow_forwardA 118 kg box sits on a flat surface where it has a static friction coefficient of μs = 0.524 and a kinetic friction coefficient of μk = 0.318. What is the minimum horizontal force that a worker must apply in order to get the box to begin moving?arrow_forwardIf F = 40 N and M = 2.0 kg, what is the magnitude of the acceleration of the suspended object? All surfaces are frictionless.arrow_forward
- A 118 kg box sits on a flat surface where it has a static friction coefficient of us = 0.524 anda kinetic friction coefficient of Mx = 0.318. What is the minimum horizontal force that a worker mustapply in order to get the box to begin moving?arrow_forwardA student of weight 651 N rides a steadily rotating Ferris wheel (the student sits upright). At the highest point, the magnitude of the normal force ?→?F→N on the student from the seat is 586 N. (a) What is the magnitude of ?→?F→N at the lowest point? If the wheel's speed is doubled, what is the magnitude FN at the (b) highest and (c) lowest point?arrow_forwardInitially, a warehouse worker pushes a 55 [N] box on a flat, rough, horizontal surface just enough so that the box moves with a constant velocity of 4.2 [m/s].However, he gets tired and suddenly stops pushing the box. With the coefficient of kineticfriction between the box and the surface equal to 0.45, how long does it take for the box tostop? A. 0.95 [s]B. 2.1 [s]C. 4.4 [s]D. 9.3 [sarrow_forward
- A 0.400-kg pendulum bob passes through the lowest part of its path at a speed of 3.00 m/s. (a) What is the tension in the pendulum cable at this point if the pendulum is 80.0 cm long? (b) When the pendulum reaches its highest point, what angle does the cable make with the vertical? (c) What is the tension in the pendulum cable when the pendulum reaches its highest point?arrow_forwardA loudspeaker of mass 25.0 kg is suspended a distance of h = 1.00 m below the ceiling by two cables that make equal angles with the ceiling. Each cable has a length of l = 2.50 m . Q: What is the tension T in each of the cables? Use 9.80 m/s2 for the magnitude of the free-fall acceleration.arrow_forwardA chandelier with mass mmm is attached to the ceiling of a large concert hall by two cables. Because the ceiling is covered with intricate architectural decorations (not indicated in the figure, which uses a humbler depiction), the workers who hung the chandelier couldn't attach the cables to the ceiling directly above the chandelier. Instead, they attached the cables to the ceiling near the walls. Cable 1 has tension T1T1T_1 and makes an angle of θ1θ1theta_1 with the ceiling. Cable 2 has tension T2T2T_2 and makes an angle of θ2θ2theta_2 with the ceiling. Find an expression for T1T1T_1, the tension in cable 1, that does not depend on T2T2T_2. Express your answer in terms of some or all of the variables mmm, θ1θ1theta_1, and θ2θ2theta_2, as well as the magnitude of the acceleration due to gravity ggg. You must use parentheses around θ1θ1theta_1 and θ2θ2theta_2, when they are used as arguments to any trigonometric functions in your answer.arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781305952300Author:Raymond A. Serway, Chris VuillePublisher:Cengage LearningCollege PhysicsPhysicsISBN:9781285737027Author:Raymond A. Serway, Chris VuillePublisher:Cengage Learning