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A typical World War I biplane fighter (such as the French SPAD shown in Figure 3.50) has a number of vertical interwing struts and diagonal bracing wires. Assume for a given airplane that the total length for the vertical struts (summed together) is 25 ft. and that the struts are cylindrical with a diameter of 2 in. Assume also that the total length of the bracing wires is 80 ft. with a cylindrical diameter of
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Fundamentals of Aerodynamics
- A simple log bridge in a remote area consists of 2 parallel logs with planks across them. The log has an average diameter of 300 mm. A truck moves slowly across the bridge, which spans 2.5 m. Assume that the weight of the truck is equally distributed between the 2 legs. Because the wheel base of the truck is greater than 25 m. Only 1 set of the wheels is on the bridge at a time. Thus, the wheel load on one log is equivalent to a concentrated load acting at any position along the span. In addition, the weight of 1 log and the plank it supports in equivalent to a uniform load of 65 kN/m acting on the log. 1. Determine the max permissible wheel load W based upon the allowable bending stress of of 7MPa. 2. Determine the max permissible wheel load W based upon the allowable shear stress of of 0.75MPa. 3. Determine the max permissible wheel load W based upon the allowable deflection of 6mm. E=7380 MPaarrow_forwardSome idiot created the three-legged table shown. X = 0 X = l W Which of the which of the legs supports about half of the table's weight? O The far leg O The left leg None. Each supports close to one-third of the table's weight. O The right leg None. Each supports approximately the entire tabe's weight.arrow_forwardA uniform horizontal strut weighs 370.0 N. One end of the strut is attached to a hinged support at the wall, and the other end of the strut is attached to a sign that weighs 170.0 N. The strut is also supported by a cable attached between the end of the strut and the wall. Assume that the entire weight of the sign is attached at the very end of the strut. 30° Restaurant Find the tension in the cable (in N). Find the force (in N) at the hinge of the strut. (Give the direction in degrees counterclockwise from the +x-axis. Assume that the +x-axis is to the right.) magnitude direction °counterclockwise from the +x-axisarrow_forward
- The man in the figure below is pulling a drum over a circular hill. All surfaces are smooth (no friction forces). If the drum weighs 60N, what is the tension on the rope for the drum position shown?arrow_forwardTwo builders carry a sheet of drywall up a ramp. Assume that W = 1.9 m, L = 3.3 m, theta = 19.0⁰, and that the lead builder carries a weight of 109.0 N (24.5 lb). L- Ө What is the weight carried by the builder at the rear? HINT: Consider the drywall to have no thickness. The builder at the rear gets tired and suggests that the drywall should be held by its narrow side. ~W~ 0 What is the weight he must now carry? HINT: From the previous problem, you know how much each builder carries. Therefore you know the total weight. Set the sum of the torques about the front lower corner to 0, so that you do not need to know the weight carried by the builder in front.arrow_forwardP236 - The gate below is an isosceles triangle with 3m side. What is the proper configuration, the triangulate upright or inverted, so that the forces are as minimal as possible? - What would the forces be like in a circular 3m radius floodgate?arrow_forward
- Consider the figure shown below. If the weight of the picture frame is 10 N, What is the tension (T) in the string used to hang the frame? assume the angle is 30 degreesarrow_forwardA uniform, 7.5-m-long beam weighing 6490 N is hinged to a wall and supported by a thin cable attached 1.5 m from the free end of the beam. The cable runs between the beam and the wall and makes a 40° angle with the beam. What is the tension in the cable when the beam is at an angle of 30° above the horizontal?arrow_forwardProblem 4.30 While the stiffness of an elastic cord can be quite constant (i.e., the force versus displace- ment curve is a straight line) over a large range of stretch, as a bungee cord is stretched, it softens; that is, the cord tends to get less stiff as it gets longer. Assuming a soften- ing force-displacement relation of the form k8 - B83, where 8 (measured in ft) is the displacement of the cord from its unstretched length, considering a bungee cord whose unstretched length is 150 ft, and letting k = 2.58 lb/ft, determine the value of the con- stant B such that a bungee jumper weighing 170 lb and starting from rest gets to the bottom of a 400 ft tower with zero speed.arrow_forward
- The pressure vessel shown below is being lifted by two cables that are attached to the bottom of the tank at points L = 6' away from each other. Assume that this causes reaction forces at the bottom of the tank that are oriented in the direction of the cable, i.e. 30 degrees from vertical. The tank weighs 4,970 lb. For simplicity, assume that the weight is evenly distributed from one connection point to the other, thus ignoring any weight in the end caps. Also assume that the tank is pressurized to 272 psi. The tank has an internal radius of 1.7 ft and a thickness of 1/8 inch. The tank is made out of steel with a 50 ksi yield strength. Determine 1) the combined stress state at point C, which is located at mid-length at the bottom of the tank and 2) the factor of safety against yielding at point C using the Tresca criterion. In your work, be sure to clearly indicate your answers to parts 1 and 2. Please insert the factor of safety.arrow_forwardThe pressure vessel shown below is being lifted by two cables that are attached to the bottom of the tank at points L = 6' away from each other. Assume that this causes reaction forces at the bottom of the tank that are oriented in the direction of the cable, i.e. 30 degrees from vertical. The tank weighs 4,970 lb. For simplicity, assume that the weight is evenly distributed from one connection point to the other, thus ignoring any weight in the end caps. Also assume that the tank is pressurized to 272 psi. The tank has an internal radius of 1.7 ft and a thickness of 1/8 inch. The tank is made out of steel with a 50 ksi yield strength. Determine 1) the combined stress state at point C, which is located at mid-length at the bottom of the tank and 2) the factor of safety against yielding at point C using the Tresca criterion. be sure to clearly indicate your answers to parts 1 and 2.arrow_forward(2) Force P = 100 lb, is applied to a small pulley that rolls freely (no friction) on cable ACB. If the tension in the cable is 100 lb: a) What is the tension in the cable? 30°arrow_forward
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