Question 31 Answer and Explanation _ACT June 2022 Form E26 Science Section

Passage V

A structural beam, such as one used in construction, will deflect (bend) when a sufficiently large force is applied perpendicular to the beam’s length. Three studies of 12 trials each were performed on the deflection of 2 straight structural beams—a concrete beam and a steel beam—that had identical dimensions.

In each trial, 2 supports were separated by a distance L, measured in centimeters (cm), and a beam was centered on top of the supports. A force, F, measured in kilonewtons (kN), was then applied to the center of the beam, and the maximum deflection of the beam, d, was measured in millimeters (mm). See the apparatus diagram.

Study 1

Twelve trials were performed in which L was varied and F was 1 kN. In the first 6 trials, the concrete beam was tested in the H configuration. In the last 6 trials, the concrete beam was tested in the I configuration. Figure 1 shows the results of these trials.

Study 2

In 12 trials, the procedures of Study 1 were repeated, except that the steel beam was tested. Figure 2 shows the results of these trials.

Study 3

Twelve trials were performed in which L was 100 cm and F was varied. In the first 6 trials, the concrete beam was tested in the I configuration. In the last 6 trials, the steel beam was tested in the I configuration. Figure 3 shows the results of these trials.

31. Suppose that in Study 3 the 2 beams had been tested in the H configuration. How would the results most likely have compared with the data shown in Figure 3 ? For each beam, the graph of d versus F would have been a straight line whose slope was:

A. negative, and the line would have been steeper than the corresponding line graphed in Figure 3.

B. negative, and the line would have been less steep than the corresponding line graphed in Figure 3.

C. positive, and the line would have been steeper than the corresponding line graphed in Figure 3.

D. positive, and the line would have been less steep than the corresponding line graphed in Figure 3.

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

According to Figure 1&2, it can be seen that under the action of F, both beams will increase with the increase of L, so it is positively correlated; the deformation of H is more obvious than that of I, so H corresponds to the steeper curve; choose C