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A group of students conducted several experiments using a variety of nonstick cookware, a spring scale, and several different weighted objects. Their goal was to determine which brand of cookware products had the best nonstick surface by measuring the coefficient of static friction, which is a measure of how resistant a stationary object is to movement.
A student connected the spring scale to a weighted object that was placed inside a piece of nonstick cookware as shown in Figure 1.
The students planned to calculate the coefficient of static friction by determining the force required to disturb an object from rest. During the experiment, one student anchored the nonstick cookware be holding tightly to the handle while the other student attached a weighted, smooth steel object to the spring scale. The student pulled on the spring until the object began to move. A third student recorded the force in newtons, N, indicated on the spring scale at the moment the object began to move across the nonstick surface.
This procedure was repeated for 3 different brands of cookware; each brand of cookware was tested with various weighted objects. The coefficient of static friction was calculated by dividing the average force required to move the object by its weight (mass × g, the gravitational constant). The results are shown in Table 1.
The students performed an experiment similar to Experiment 1, except three different brands of cooking spray were applied to the same cookware surface before the weights were put in place. The results are shown in Table 2.
. The results of the 2 experiments support the conclusion that as the weight of an object increases, the average force required to move it from rest generally:
H. varies, with no particular trend.
J. remains constant.
. If Experiment 1 was repeated for Brand B cookware with a 200 gram mass, the average force needed to disturb the object from rest would be closest to:
A. 0.03 N.
B. 0.06 N.
C. 0.12 N.
D. 0.18 N.
. Based on the results of Experiments 1 and 2, which of the following combinations would result in the surface with the least coefficient of static friction?
F. Cookware brand A and cooking spray brand X.
G. Cookware brand B and cooking spray brand Y.
H. Cookware brand C and cooking spray brand Y.
J. Cookware brand C and cooking spray brand Z.
. Which brand(s) of cooking spray was/were tested with only 2 different weights in Experiment 2?
A. Brand Y only.
B. Brand Z only.
C. Brands X and Y only.
D. Brands X and Z only.
. According to the passage, for the students to accurately measure the coefficient of static friction, which force would have to be overcome?
F. The weight of the object.
G. The force between the spring scale and the object.
H. The force of applying the cooking spray to the surface.
J. The force required to disturb the object from rest.
. The students’ instructor gave them one piece of nonstick cookware and asked them to identify the brand. The students repeated the procedures followed in Experiment 1 and obtained average forces of 0.088 N for the 150 gram object and 0.149 N for the 250 gram object. Which of the following brands would most likely have produced these results?
A. Brand B only.
B. Brand C only.
C. Brand A and C only.
D. Brand B and C only.
. The best answer is G.
According to Tables 1 and 2, as the weight of the object increases (going down the column) for each brand, the average force required to move the object also increases. In other words, there is a direct relationship.
. The best answer is C.
Table 1 shows that for brand B cookware, when the mass of the weighted object was 150 g and 250 g, the aver- age force required to move the object was 0.090 N and 0.147 N, respectively. Because 200 g is in between 150 g and 250 g, you would expect the force needed to move an object that has a mass of 200 g to be between 0.090 and 0.147 N. Answer choice C (0.12 N) is the only answer choice within this range.
. The best answer is H.
The results from Table 1 show that brand C cookware has the smallest coefficient of static friction. The results from Table 2 show that brand Y cooking spray has the smallest coefficient of static friction. This information suggests that these two brands, if combined, would result in the surface with the least coefficient of static friction.
. The best answer is B.
Table 2 shows the results of Experiment 2. In the table, brands X and Y were both tested with 50 g, 150 g, and 250 g objects. Brand Z, however, was only tested with 150 g and 250 g objects. Answer choice B is correct because only brand Z cooking spray was tested with only 2 different weights in Experiment 2.
. The best answer is J.
The Experiment states: “The students planned to calculate the coeffi- cient of static friction by determining the force required to disturb an object from rest.” Answer choice H can be eliminated because the coeffi- cient of static friction could be determined in both experiments, but cooking spray was only used in Experiment 2.
. The best answer is A.
According to Table 1, brand B cookware had an average force of 0.090 N for the 150 g weight and 0.147 N for the 250 g weight. These results are the closest to the results the students obtained when their instructor gave them the new piece of nonstick cookware.