Berkeley Review Physics Example Question

[Live4Life]

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For example 2.4b on Volume I of the physics review book, can someone explain to me whether the tension of the elevator cable increases linearly (choice A) or exponentially (choice B) and why? I was thinking linearly (answer A) since F=ma and if the acceleration increases, then a proportional increase in the force can be expected.


For those that don't have the book, the question states:

Which graph Best represents the relationship between the cable tension and the magnitude of upward acceleration of an elevator? The cable is used to support the elevator and move the elevator. The graph is tension (force) vs. acceleration (x-axis).

Choice A: Increases linearly (I believe this is true)
Choice B: Increases exponentially
Choice C: Decreases linearly (WRONG)
Choice D: Constant (WRONG)

 

[BerkReviewTeach]

For example 2.4b on Volume I of the physics review book, can someone explain to me whether the tension of the elevator cable increases linearly (choice A) or exponentially (choice B) and why? I was thinking linearly (answer A) since F=ma and if the acceleration increases, then a proportional increase in the force can be expected.


For those that don't have the book, the question states:

Which graph Best represents the relationship between the cable tension and the magnitude of upward acceleration of an elevator? The cable is used to support the elevator and move the elevator. The graph is tension (force) vs. acceleration (x-axis).

Choice A: Increases linearly (I believe this is true)
Choice B: Increases exponentially
Choice C: Decreases linearly (WRONG)
Choice D: Constant (WRONG)

The only forces of concern are all in the y-direction. The net force, Fnet, is T - mg. Assuming that mg is constant (nothing enters or exits the elevator compartment), then Fnet is directly proportional to T. The relationship is linear, so choice A is the best answer.

What version of the books do you have? I ask, because the answer key location to the b-questions was moved from a few editions ago.

 

[Live4Life]

The only forces of concern are all in the y-direction. The net force, Fnet, is T - mg. Assuming that mg is constant (nothing enters or exits the elevator compartment), then Fnet is directly proportional to T. The relationship is linear, so choice A is the best answer.

What version of the books do you have? I ask, because the answer key location to the b-questions was moved from a few editions ago.

I have the newest edition I think, which says that the answers to part B examples are in the back of the book but I didn't find them there so I don't know where they are.

 

[BerkReviewTeach]

I have the newest edition I think, which says that the answers to part B examples are in the back of the book but I didn't find them there so I don't know where they are.

Try page 282 in book 1.