Passage V

If an object is at rest and the sum of the forces acting on it is zero, the object is in a state of static equilibrium. In each trial of 2 experiments on static equilibrium, 3 cables and a cylinder were arranged as shown in Figure 1.

Cables 1, 2, and 3, each with its own tensiometer (a device used to measure tension), were joined with a single knot, The free ends of Cables 1 and 2 were attached to an L-shaped support, and a cylinder of mass M was suspended from the free end of Cable 3. Cable 1 made an angle with the top of the support, and Cable 2 made a 90° angle with the side of the support. None of the cables stretched under tension. The tension forces acting on the knot, which was in static equilibrium, are shown in Figure 2.

The tension in Cable 1, , had a horizontal component, and a vertical component, · The tension in Cable 2, , was purely horizontal, and the tension in Cable 3, , was purely vertical.

Experiment 1

In Trials 1-5, M was 1.0 kg and 0 was varied. Table 1 lists , in degrees, as well as , , , and , each in newtons (N), for each trial.

Experiment 2

In Trials 6-10, M was varied and was 50°. Table 2 lists M as well as , , , and for each trial.

31. Suppose that in Experiment 2 a trial had been performed in which was 68.6 N. The mass of the cylinder in this trial would most likely have been:

Answer and Explanation

Your Answer is

Correct Answer is B

Explanation

As can be seen from table 2, the larger T1y is, the larger M will be. And every time T1y increases by about 10 N, M increases by 1 kg per month;

T1y given in the question stem is 68.6 N, so the corresponding M should be about 1 kg larger than M in trial 10 , about 6+1=7 kg, so option B meets