Frrquency vs period

[inaccensa]

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I want to know why we use frequency to base our calculations for the first problem. I did the same thing with period and found that the period increases

The KE energy, there is a similar graph in EK book, but lets say if this graph were on the exam, what would you select?

 

[FutureDoctor503]

You can use either one since f = 1/T.

 

[liveoak]

i would select C as negative kinetic energy seems silly.

 

[FutureDoctor503]

i would select C as negative kinetic energy seems silly.

Yes, I realized that. C seems like the best answer. We can rule out A and B.

 

[inaccensa]

You can use either one since f = 1/T.

but then the answers differ

 

[FutureDoctor503]

but then the answers differ

Can you explain how you approached this problem?

 

[inaccensa]

Yes, I realized that. C seems like the best answer. We can rule out A and B.

In that case, what exactly are you presuming the baseline to be?

 

[FutureDoctor503]

In that case, what exactly are you presuming the baseline to be?

will repost in a minute

 

[FutureDoctor503]

Does this help?

 

[costales]

Kinetic energy is zero where the motion changes direction, but it can't be negative. It is C.

 

[inaccensa]

Does this help?

Definitely helped..thanks. They drew two waves one for PE and one KE that look like negative interference. The graph makes sense when you look at it in-relation to the two. Just one more q, if C was a choice and had the wave in D was drawn such that the trough touched the X axis, then would it correct to choose either as an answer?

 

[inaccensa]

Can we also draw this graph show the equlibrium position? Where KE will be crest and PE the trough

 

[inaccensa]

You can use either one since f = 1/T.

Yeah that is true, but based on the q, how can one extrapolate whether they are asking for frequency or period? Period will increase and frequency decreases, but based on the answer choices, how will I pick the answer?

 

[MD Odyssey]

Yeah that is true, but based on the q, how can one extrapolate whether they are asking for frequency or period? Period will increase and frequency decreases, but based on the answer choices, how will I pick the answer?

Well, the period of a pendulum is proportional to the square root of its length divided by the gravitational constant, so if you put something like a grandfather clock 100,000 km above the Earth, its clearly going to take longer to make one oscillation. This would appear to an observer that it was running slower. I think you may be trying to read too much into the question.

Edit: I suppose if the test writer was trying to be really clear, they might choose to specify that you are to consider the period, but part of physics is being able to use your intuition that says if I increase the gravitational force on the pendulum, it's going to run faster.

 

[FutureDoctor503]

Definitely helped..thanks. They drew two waves one for PE and one KE that look like negative interference. The graph makes sense when you look at it in-relation to the two. Just one more q, if C was a choice and had the wave in D was drawn such that the trough touched the X axis, then would it correct to choose either as an answer?

Yes!!! 🙂

 

[FutureDoctor503]

double post

 

[inaccensa]

You guys are the best🙂 What would i do without your help🙂

 

[MD Odyssey]

You guys are the best🙂 What would i do without your help🙂

Probably read your textbook more, Google some, and figure it out on your own. 🙂