# Problem 555 part a a bag of groceries is on the seat

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Problem 5.55Part AA bag of groceries is on the seat of your car as you stop for a stop light. The bag does not slide. Draw a free­body diagram for the bag.Draw the force vectors with their tails at the dot. The orientation of your vectors will be graded. The exact length of your vectors will not begraded but the relative length of one to the other will be graded.ANSWER:18More than 180Less than 18but greater than 0
Typesetting math: 100%
9/6/2016Homework3­29/21CorrectMechanical Equilibrium ProblemsA pair of students are lifting a heavy trunk on move­in day. Using two ropes tied to a small ring at thecenter of the top of the trunk, they pull the trunk straight up at a constant velocity. Each ropemakes an anglewith respect to the vertical. The gravitational force acting on the trunk hasmagnitude.The trunk is moving at a constant velocity. This means that you can model it as a particle in dynamic equilibrium. Furthermore, you can ignore the masses ofthe ropes and the ring because it is reasonable to assume that their combined weight is much less than the weight of the trunk.Part AThe most convenient coordinate system for this problem is one in which theyaxis is vertical and the ropes both lie in thexyplane, as shown below.Identify the forces acting on the trunk, and then draw a free­body diagram of the trunk in the diagram below. The black dot represents the trunk as it islifted by the students.Draw the vectors starting at the black dot. The location and orientation of the vectors will be graded. The length of the vectors will not begraded.ANSWER:Typesetting math: 100%
9/6/2016Homework3­2CorrectPart BIn the free­body diagram drawn in the previous part, different symbols are used to represent the tensions in the two ropes. This notation could be simplifiedby identifying a useful relationship between these two forces. Which of the following statements properly describes the relationship between the magnitudeof the tension force in rope 1 and the magnitudeof the tension force in rope 2?
10/21CorrectThis is a type of reasoning, used often in physics, called asymmetry argument. Since the ropes are in identical situations, except for one being themirror image of the other, they have to possess identical tensions. Since the two tension forces have equal magnitude, just useto denote themagnitude of the tension force in either rope. With the information you have gathered here, you can build a complete pictorial representation:Part C

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