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A car is stuck in the mud. A tow truck pulls on the car with the arrangement shown in Fig. P4.32. The tow cable is under a tension of 2 500 N and pulls downward and to the left on the pin at its upper end. The light pin is held in equilibrium by forces exerted by the two bars A and B. Each bar is a strut; that is, each is a bar whose weight is small compared to the forces it exerts and which exerts forces only through hinge pins at its ends. Each strut exerts a force directed parallel to its length. Determine the force of tension or compression in each strut. Proceed as follows. Make a guess as to which way (pushing or pulling) each force acts on the top pin. Draw a free-body diagram of the pin. Use the condition for equilibrium of the pin to translate the free-body diagram into equations. From the equations calculate the forces exerted by struts A and B. If you obtain a positive answer, you correctly guessed the direction of the force. A negative answer means that the direction should be reversed, but the absolute value correctly gives the magnitude of the force. If a strut pulls on a pin, it is in tension. If it pushes, the strut is in compression. Identify whether each strut is in tension or in compression.
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Chapter 4 Solutions
Principles of Physics: A Calculus-Based Text
- Two blocks, each of mass m = 3.50 kg, are hung from the ceiling of an elevator as in Figure P4.33. (a) If the elevator moves with an upward acceleration a of magnitude 1.60 m/s2, find the tensions T1 and T2 in the upper and lower strings. (b) If the strings can withstand a maximum tension of 85.0 N, what maximum acceleration can the elevator have before a string breaks? Figure P4.33 Problems 33 and 34.arrow_forwardA 2 kg box is against a vertical wall by a small force (f1=10n) perpendicular to the surface of the wall, and pushed upward by a force. Force applied to the box vertically. The force pushes the box and the wall. Determine the value of the applied force to keep the box moving upward at a constant velocityarrow_forwardIn the figure, a 1.70 kg ball is connected by means of two massless strings, each of length L = 1.13 m, to a vertical, rotating rod. The strings are tied to the rod with separation d = 1.13 m and are taut. The tension in the upper string is 59.0 N. What are (a) the tension in the lower string, (b) the magnitude of the net force F net on the ball, and (c) the speed of the ball? d Rotating rod (a) Number Units (b) Number Units (c) Number Unitsarrow_forward
- A 20.0 kg box is held at rest by two ropes that form 30 degree angles with the vertical. An external force F of magnitude 300 N is also applied vertically downward on the box. The force exerted by each of the two ropes is denoted by T. A force diagram, showing the four forces that act on the box in equilibrium, is shown in the figure. You may take g=10m/s/s. Find the tension in the ropes.arrow_forwardThe 1.0 kg block in the figure is tied to the wall with a rope. It sits on top of the 2.0 kg block. The lower block is pulled to the right with a tension force of 20 N. The coefficient of kinetic friction at both the lower and upper surfaces of the 2.0 kg block is μkμkmu_k = 0.42. What is the tension in the rope holding the 1.0 kg block to the wall? Express your answer with the appropriate units. What is the acceleration of the 2.0 kg block? Express your answer with the appropriate units.arrow_forwardTwo masses m1 = .5kg and m2 = .2kg are attached by an unstretchable string over a mass-less pulley. m1 hangs over the edge not touching any surfaces. m2 sits on the surface of the table with a coefficient of friction of μ = .1. A second string attached to m2 is pulled horizontally to accelerate the masses away from the edge. If the tension of T2 is 5.6N what is the acceleration?What is T1, the string between the two masses?arrow_forward
- the steel I-beam in the drawing has a weight of 1.51 X 103 N and is being lifted at a constant velocity. What is the tension in each cable attached to its ends?arrow_forwardTwo boxes with masses M1 = 10 Kg and M2 = 15 Kg, connected with a massless string are placed on a frictionless table. The mass M2 is pulled with a force F = 150 N, making an angle of Θ = 25 with the surface, as shown in the figure. Calculate the tension in the string between the two boxes.arrow_forwardA traffic light of mass m = 31 kg is hanging symmetrically by two cables, which make an angle of 25 degrees with the horizontal, while holding the traffic light in place. What is the tension in each cable, as the traffic light hangs stationary.arrow_forward
- The person in Figure P4.55 weighs 170 lb. Each crutch makes an angle of 22.0° with the vertical (as seen from the front). Half of the person’s weight is supported by the crutches, the other half by the vertical forces exerted by the ground on his feet. Assuming he is at rest and the force exerted by the ground on the crutches acts along the crutches, determine (a) the smallest possible coefficient of friction between crutches and ground and (b) the magnitude of the compression force supported by each crutch.arrow_forwardA 50.0-N box is sliding on a rough horizontal floor, and there is only one horizontal force acting against the motion of the box. You observe that at one instant the box is sliding to the right at 1.75 m/s and that it stops in 2.25 s with uniform (constant) acceleration. What is the magnitude of the force acting against the motion of the box?arrow_forwardA chandelier with mass m 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 T1 and makes an angle of θ1 with the ceiling. Cable 2 has tension T2 and makes an angle of θ2 with the ceiling. Find an expression for T1, the tension in cable 1, that does not depend on T2.arrow_forward
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning