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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, Hybrid (with Enhanced WebAssign Printed Access Card)
- 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 climbing anchor consists of two strands of nylon webbing clipped to bolts in the rock. The webbing is clipped into the rope at the other end, with the webbing making angles of 22° and 35° with the vertical. What is the tension in each of the webbing strands if the combined mass of the rope and climber is 85 kg?arrow_forwardA spider hangs from the junction formed by three strands of silk, as shown in the figure. The force of tension in each strand pulls at the junction. The net force at the junction is zero. In other words, the resultant of all three force vectors is zero at the junction. The gravitational force on the spider makes it exert a downward force of 0.15 N on the junction. The two sloping strands are perpendicular to each other. We have chosen the x and y axes to be along those strands as shown. The force of the right strand on the junction has magnitude Tx force of the left strand on the junction has unknown magnitude T,y. a) Calculate Ty. b) Calculate the angle between the x axis and the horizontal direction. Hint: The SI unit of force is the newton, which is abbreviated as N. You must consider three force vectors. The x components of all three vectors must add to zero, and the y components must also add to zero. Note that the coordinate system is "rotated" which is Tx Ty 0.127 Ν. The a…arrow_forward
- An electric lamp of mass 0.8 kg is attached by an electric cable to the ceiling at point A. The lamp is pulled to one side by a string tied to the ceiling at B. The cable and string make angles of 60° and 40° respectively with the ceiling. A B 60° 40° cable string T, T, F=0.8N (i) The tension in the cable and string respectively are T¡ and T, . Find T and T, correct to two decimal places. (ii) What would be the tension in the cable if the string was removed so the lamp hangs straight down?arrow_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_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_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_forwardA magnet of mass 4.72 kg is suspended from the ceiling by a cord as shown. A large magnet is somewhere off to the right, pulling on the small hanging magnet with a constant force of F = 57.1 N. At what angle theta ?with respect to the vertical does the magnet hang? Consider the same situation as in the previous problem. This time the magnet has mass 6.62 kg and the force pulling the magnet to the right has magnitude 180.6 N. What is the magnitude of the tension force in the cord? Same situation as in the previous problem this time the magnet has mass 7.25 kg, the force pulling it to the right is 111.3 N, the cord has length 0.54 m and the ceiling is 2.82 m above the floor. How far to the right of its start point will the magnet have traveled when it hits the floor after the cord is cut? OK, one more time. This time the magnet has mass 6.78 kg and the force pulling it to the right is 175.5 N. When the magnet hits the floor, it continues being pulled to the right by the same…arrow_forward
- Two 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_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
- Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
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