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Raising a Ladder. A ladder carried by a fire truck is 20.0 m long. The ladder weighs 3400 N and its center of gravity is at its center. The ladder is pivoted at one end (A) about a pin (Fig. E11.5); ignore the friction torque at the pin. The ladder is raised into position by a force applied by a hydraulic piston at C. Point C is 8.0 m from A, and the force
Figure E11.5
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- Dima pulls directly backward with a force F=137 N on the end of a 2.00 m-long oar. The oar pivots about its midpoint. At the instant shown, the oar is completely in the ??-yz-plane and makes a 30.0∘ angle with respect to the water's surface. Derive an expression for the torque vector ?⃗ τ→ about the axis through the oar’s pivot. Express the torque using ???ijk vector notation. ?⃗ =???+???+??? ?⃗ =?N*marrow_forward11.52 · A Truck on a Drawbridge. A loaded cement mixer drives onto an old drawbridge, where it stalls with its center of gravity three-quarters of the way across the span. The truck driver radios for help, sets the handbrake, and waits. Meanwhile, a boat approaches, so the drawbridge is raised by means of a cable attached to the end opposite the hinge (Fig. P11.52). The draw- bridge is 40.0 m long and has a mass of 18,000 kg; its center of gravity is at its midpoint. The cement mixer, with driver, has mass 30,000 kg. When the drawbridge has been raised to an angle of 30° above the horizontal, the cable makes an angle of 70° with the surface of the bridge. (a) What is the tension T in the cable when the drawbridge is held in this position? (b) What are the horizontal and vertical components of the force the hinge exerts on the span? Figure P11.52 70° k100 m 40.0 m 30arrow_forwardA non-uniform beam extends horizontally from x = 0 m to x = 6.5 m. The linear mass density of the beam, as a function of x, is given by λ(x) = 17 - 3 (x / 6.5) (kg/m). Calculate the gravitational torque on the beam about its left end, in N m. Use g = 10 m/s2. Make your answer a positive number.arrow_forward
- In the figure, a lead brick rests horizontally on cylinders A and B. The areas of the top faces of the cylinders are related by AA= 2.9 Ag; the Young's moduli of the cylinders are related by EA= 2.1 EB. The cylinders had identical lengths before the brick was placed on them. What fraction of the brick's mass is supported (a) by cylinder A and (b) by cylinder B? The horizontal distances between the center of mass of the brick and the centerlines of the cylinders are dafor cylinder A and dg for cylinder B. (c) What is the ratio da/dg? da com of brick (a) Number Units (b) Number Units Units (c) Numberarrow_forwardIn the figure, a lead brick rests horizontally on cylinders A and B. The areas of the top faces of the cylinders are related by AA= 2.7 Ag; the Young's moduli of the cylinders are related by EA= 2.8 Eg. The cylinders had identical lengths before the brick was placed on them. What fraction of the brick's mass is supported (a) by cylinder A and (b) by cylinder B? The horizontal distances between the center of mass of the brick and the centerlines of the cylinders are dafor cylinder A and dg for cylinder B. (c) What is the ratio da/dg? da com of brick A В (a) Number i Units (b) Number i Units (c) Number i Units >arrow_forwardThe 38-kg homogeneous smooth sphere rests on the 40° incline A and bears against the smooth vertical wall B. Calculate the contact force at A and B. Assume = 40°. Answers: FA = FB: = Ꮎ i 498 307 B N Narrow_forward
- In the figure, a lead brick rests horizontally on cylinders A and B. The areas of the top faces of the cylinders are related by AA= 1.6 Ag; the Young's moduli of the cylinders are related by Ea= 1.8 Eg. The cylinders had identical lengths before the brick was placed on them. What fraction of the brick's mass is supported (a) by cylinder A and (b) by cylinder B? The horizontal distances between the center of mass of the brick and the centerlines of the cylinders are dafor cylinder A and dg for cylinder B. (c) What is the ratio da/dg? da dp com of brick A В (a) Number i Units (b) Number i Units (c) Number Unitsarrow_forwardIn the figure, a lead brick rests horizontally on cylinders A and B. The areas of the top faces of the cylinders are related by A4= 2.8 Ag; the Young's moduli of the cylinders are related by Ea= 2.3 Eg. The cylinders had identical lengths before the brick was placed on them. What fraction of the brick's mass is supported (a) by cylinder A and (b) by cylinder B? The horizontal distances between the center of mass of the brick and the centerlines of the cylinders are dafor cylinder A and d; for cylinder B. (c) What is the ratio da/dg? com of brick A (a) Number i Units (b) Number i Units (c) Number i Unitsarrow_forwardProblem#3: Can the system in given figure be in static equilibrium in the position shown? The uniform bar AB weighs 500 lb, and the weight of block C is 300 lb. Friction at A is negligible, and the coefficient of static friction is 0.4 at the other two contact surfaces. B C 5m 130° 50°arrow_forward
- Two cylinders of cross-scctional area A = 10 m are fitted smoothly together as shown in the Figure, and then evacuated. Masses M are hung from cables attached to cach of the cylinders. How large can the masses M be made before the cylinders are pulled apart? Marrow_forwardA tire, which is mounted on a car, has a radius of 0.23m0.23m. A nail with a mass of 11.4g11.4g is stuck in the tread of the tire, and it is held there with a maximum frictional force of 0.53N0.53N. The car has been elevated on a mechanic lift so that the tire is no longer in contact with the pavement. Part (a) What is the tire tread’s lowest tangential speed, in meters per second, at which the nail will pull free from the tire? (How does gravity affect the net force on the nail at various positions in the rotation of the tire.) Part (b) At what tangential speed, in meters per second, would the nail pull free when it is at the top of the tire? (This is a mildly silly question because the nail would have already pulled free at some other point in the rotation.)arrow_forwardM2arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning