September 2007 LSAT Section 1 Question 7

Inertia affects the flow of water pumped through a closed system of pipes. When the pump is first switched on, the wa...

aseikhon11 on October 5, 2020

A & B

It is A because they talk about cause & effect? because current flow is "affected" by inductance but not "required" as B states? B: the word require makes it a S&N? but inertia is not something thats necessary for electricity to flow but just an affect of it? This makes sense to me, but again this is LSAT prep, so I don't know if thats a good thing and if thats why it's actually right. Please help

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shunhe on October 6, 2020

Hi @aseikhon11,

Thanks for the question! So let’s take a look at the stimulus. We’re told that inertia affects water flow pumped through a closed system of pipes. When the pump goes on, the water takes time to reach full speed. Then, when the pump’s switched off, the decrease in the water flow is gradual (because of inertia). And we’re also told that the effects of inductance in electrical circuits are similar to the effects of inertia in water pipes.

So this is a fact set, not an argument, there’s not really a conclusion here. And we’re asked for find something that’s most supported by these facts as presented (remember, no outside information allowed!). So we probably want to find something telling us about how electricity moves.

Now take a look at (A), which tells us that the rate at which electrical current flows is affected by inductance. Well, this is supported! Because we know that inertia affects water flow. And we know that inductance is like inertia for electrical circuits. So inductance probably affects electrical current flow! It’s not about cause and effect, it’s about being the analogy set up in the facts. ??(B), on the other hand, isn’t most supported. It tells us that the flow of electrical current in a circuit requires inertia. But we only know about inertia with respect to water flow, not with respect to electrical circuits. Nothing tells us electrical circuits need inertia. We just know that inductance is like inertia for electrical circuits. So (B) isn’t supported by the facts and is incorrect.

Hope this helps! Feel free to ask any other questions that you might have.