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Hard Physics Questions

Anonymous Thu 13 Jan 03:11:13 2022 No.14094866 View Reply Original Report

Quoted By: >>14094880 >>14094895 >>14094898 >>14095030

This is a question I remember getting and not being to solve it. How in the world would anybody figure the answer was 1.2 m/s? Without any damn time?

Anonymous

Anonymous Thu 13 Jan 2022 03:15:28 No.14094880 Report

Quoted By: >>14094890

>>14094866
mgh=1/2mv^2

Anonymous

Anonymous Thu 13 Jan 2022 03:19:59 No.14094890 Report

Quoted By:

>>14094880
Conservation of Energy?

Anonymous

Anonymous Thu 13 Jan 2022 03:23:21 No.14094895 Report

Quoted By:

>>14094866
I guess you're supposed to assume that when released, the cylinder will convert the potential energy difference from 1.932m to 2.000m into velocity, so you'd try to remember the formula that has gravitational potential energy and velocity in it and solve for velocity.

Anonymous

Anonymous Thu 13 Jan 2022 03:23:41 No.14094898 Report

Quoted By:

>>14094866
Use conservation of energy: at the bottom of the swing all the potential energy is converted into kinetic.
$mg \Delta h = \frac{1}{2} mv^2 \\ v = \sqrt{2g \Delta h } = 1.2$

Anonymous

Anonymous Thu 13 Jan 2022 04:09:16 No.14095030 Report

Quoted By: >>14095038 >>14095076

>>14094866
>Hard Physics Questions
>Picks just about the easiest conservation of energy question possible

Anonymous

Anonymous Thu 13 Jan 2022 04:11:21 No.14095038 Report

Quoted By: >>14095055 >>14095078

>>14095030
Then solve it step by step if it's so "easy".

Anonymous

Anonymous Thu 13 Jan 2022 04:16:14 No.14095055 Report

Quoted By: >>14095068 >>14095074 >>14095077

>>14095038
a) center of mass goes from 2m below pivot to 1.932m below it. So a height of .068m above old position.
The gain in GPE is mgh, or (.08kg) * (10m/s^2) * (.068m) = .0544 J

b) using conservation of energy, the energy lost when it swings back down must be gained as kinetic energy.
.0544 = 1/2 m v^2, or v = sqrt(.0544*2/.08) = 1.66 m/s

Anonymous

Anonymous Thu 13 Jan 2022 04:20:12 No.14095068 Report

Quoted By:

>>14095055
>1.66 m/s
lol

Anonymous

Anonymous Thu 13 Jan 2022 04:21:38 No.14095074 Report

Quoted By:

>>14095055
Why the hell would they put the triangle delta behind the h though? Why make things more complicated?

Anonymous

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Anonymous Thu 13 Jan 2022 04:22:52 No.14095076 Report

Quoted By: >>14095078

>>14095030
KEi + PEi = KEf + PEf

simple as

Anonymous

Anonymous Thu 13 Jan 2022 04:23:33 No.14095077 Report

Quoted By: >>14095100

>>14095055
>1.66 m/s
You done fucked up bro

Anonymous

Anonymous Thu 13 Jan 2022 04:24:10 No.14095078 Report

Quoted By:

>>14095038
>>14095076
quoted wrong post, sorry

posting is less simple than Newtonian physics, apparently

Anonymous

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Anonymous Thu 13 Jan 2022 04:28:41 No.14095097 Report

Quoted By: >>14095123

Ok here's a harder physics problem

Anonymous

Anonymous Thu 13 Jan 2022 04:29:54 No.14095100 Report

Quoted By: >>14095103 >>14095107

>>14095077
>ecf
>meaning to correct to the nearest
All of you dropped out of college including OP

Anonymous

Anonymous Thu 13 Jan 2022 04:31:18 No.14095103 Report

Quoted By:

>>14095100
You fucked up the digits you dyslexic retard. Check your calculator again.

Anonymous

Anonymous Thu 13 Jan 2022 04:33:39 No.14095107 Report

Quoted By: >>14095135 >>14095148 >>14095153

>>14095100
>ecf
>meaning to correct to the nearest
ECF means "error carried forward", that is if you've made a numerical error in the previous question, and then brought it forward to the current question, you should still be given the mark for it. In this case it would be incorrectly calculating $\Delta h$ and then using that value in the next question.

Anonymous

Anonymous Thu 13 Jan 2022 04:37:57 No.14095123 Report

Quoted By:

>>14095097
a=ng

Anonymous

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Anonymous Thu 13 Jan 2022 04:40:55 No.14095135 Report

Quoted By: >>14095152 >>14095155

>>14095107
Okay what about this?

Anonymous

Anonymous Thu 13 Jan 2022 04:44:55 No.14095148 Report

Quoted By: >>14095153

>>14095107
Okay good but what about this?

Anonymous

Anonymous Thu 13 Jan 2022 04:45:25 No.14095152 Report

Quoted By:

>>14095135
Air resistance dumbass

Anonymous

View Same Google iqdb SauceNAO this is easy but ii is hard.jpg, 64KiB, 733x580

Anonymous Thu 13 Jan 2022 04:45:56 No.14095153 Report

Quoted By: >>14095156

>>14095107
>>14095148

Anonymous

Anonymous Thu 13 Jan 2022 04:46:54 No.14095155 Report

Quoted By:

>>14095135
$v = \frac{d}{t} = \frac{2.5 \times 10^{-2}}{22 \times 10^{-3}} = 1.14 ms^{-1}$
So the "actual" speed is less than what we calculate. Probably due to air resistance.

Anonymous

Anonymous Thu 13 Jan 2022 04:46:59 No.14095156 Report

Quoted By:

>>14095153
Not just that but it's also width of cylinder

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