In figure 1, the winch is mounted on an axle, and the 6-sided nut is welded to the winch. By turning the nut with a wrench, a person can rotate the winch. For instance, turning the nut clockwise lifts the block off the ground, because more and more rope gets wrapped around the winch.
Three students agree that using a longer wrench makes it easier to turn the winch. But they disagree about why. All three students are talking about the case where the winch is used, over a 10-second time interval, to lift the block one meter off the ground.
Student 1
By using a longer wrench, the person decreases the average force he must exert on the wrench, in order to lift the block one meter in ten seconds.
Student 2
Using a longer wrench reduces the work done by the person as he uses the winch to lift the block one meter in ten seconds.
Student 3
Using a longer wrench reduces the power that the person must exert to lift the block one meter in ten seconds.
FIGURE 1
FIGURE 2
Wrench turns winch clockwise

1. | Student 1 is:

A. | Correct, because the torque that the wrench must exert to lift the block doesn't depend on the wrench's length.

B. | Correct, because using a longer wrench decreases the torque it must exert on the winch.

C. | Incorrect, because the torque that the wrench must exert to lift the block doesn't depend on the wrench's length.

D. | Incorrect, because using a longer wrench decreases the torque it must exert on the winch.

2. | Which of the following is true about students 2 and 3?

A. | Students 2 and 3 are both correct.

B. | Student 2 is correct, but student 3 is incorrect.

C. | Student 3 is correct, but student 2 is incorrect.

D. | Students 2 and 3 are both incorrect.

3. | If several wrenches all apply the same torque to a nut, which graph best expresses the relationship between the force the person must apply to the wrench, and the length of the wrench?

A. | A

B. | B

C. | C

D. | D

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