Hovercraft B/C

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Re: Hovercraft B/C

Post by UTF-8 U+6211 U+662F » May 3rd, 2018, 4:57 pm

photolithoautotroph wrote:If nobody posts a question in this long, you can.
Derive a formula for the acceleration of the blocks in a real atwood machine with two masses of mass [math]m1[/math] and [math]m2[/math]and a pulley in the shape of a uniform disk of mass [math]M[/math] and radius [math]r[/math]. The string is massless. Ignore friction.
The acceleration of m1 where positive is down is 
EDIT: Whoops, didn't see other answer

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Re: Hovercraft B/C

Post by PW240.3 » May 7th, 2018, 2:35 pm

photolithoautotroph wrote:If nobody posts a question in this long, you can.
Derive a formula for the acceleration of the blocks in a real atwood machine with two masses of mass [math]m1[/math] and [math]m2[/math]and a pulley in the shape of a uniform disk of mass [math]M[/math] and radius [math]r[/math]. The string is massless. Ignore friction.

Since you have to account for the pulley's moment of inertia, wouldn't the a be a=(m1-m2)g/(m1+m2+M/4)
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Re: Hovercraft B/C

Post by IvanGe » May 7th, 2018, 6:18 pm

I'm just going to ask a question because no one's verified the answer.

With what constant velocity can a 4.00 hp motor raise a mass of 125 kg?
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Re: Hovercraft B/C

Post by Adi1008 » May 7th, 2018, 10:31 pm

IvanGe wrote:I'm just going to ask a question because no one's verified the answer.

With what constant velocity can a 4.00 hp motor raise a mass of 125 kg?
2.43 meters per second
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Re: Hovercraft B/C

Post by IvanGe » May 8th, 2018, 5:36 am

Adi1008 wrote:
IvanGe wrote:I'm just going to ask a question because no one's verified the answer.

With what constant velocity can a 4.00 hp motor raise a mass of 125 kg?
2.43 meters per second

that's what i got, but the answer key said 2.76 m/s?

Anyways, your turn
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Re: Hovercraft B/C

Post by UTF-8 U+6211 U+662F » May 9th, 2018, 1:19 pm

Adi1008 wrote:
IvanGe wrote:I'm just going to ask a question because no one's verified the answer.

With what constant velocity can a 4.00 hp motor raise a mass of 125 kg?
2.43 meters per second
Can you explain this one

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Re: Hovercraft B/C

Post by Tesel » May 9th, 2018, 1:32 pm

UTF-8 U+6211 U+662F wrote:
Adi1008 wrote:
IvanGe wrote:I'm just going to ask a question because no one's verified the answer.

With what constant velocity can a 4.00 hp motor raise a mass of 125 kg?
2.43 meters per second
Can you explain this one
So the first thing to understand is that hp is a unit of power, just not an SI unit. 1 hp = 745.7 W.
From here, we can use this relationship P = Fv to solve the equation.


The reason this works is that power is really a unit of energy per time. Energy, meanwhile, is a unit of force over a distance. So, power is a unit of force over a distance per time; the distance per time corresponds to velocity.
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Re: Hovercraft B/C

Post by UTF-8 U+6211 U+662F » May 9th, 2018, 1:34 pm

Tesel wrote:
UTF-8 U+6211 U+662F wrote:
Adi1008 wrote:
2.43 meters per second
Can you explain this one
So the first thing to understand is that hp is a unit of power, just not an SI unit. 1 hp = 745.7 W.
From here, we can use this relationship P = Fv to solve the equation.


The reason this works is that power is really a unit of energy per time. Energy, meanwhile, is a unit of force over a distance. So, power is a unit of force over a distance per time; the distance per time corresponds to velocity.
Ah, I see. Thanks!

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Re: Hovercraft B/C

Post by Adi1008 » May 9th, 2018, 10:26 pm

IvanGe wrote:
Adi1008 wrote:
IvanGe wrote:I'm just going to ask a question because no one's verified the answer.

With what constant velocity can a 4.00 hp motor raise a mass of 125 kg?
2.43 meters per second

that's what i got, but the answer key said 2.76 m/s?

Anyways, your turn
Suppose I have a bowling ball with a diameter of 25 centimeters. What is the largest mass it can have such that it floats in corn syrup (specific gravity = 1.4)?
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Re: Hovercraft B/C

Post by UTF-8 U+6211 U+662F » May 10th, 2018, 12:37 pm

Adi1008 wrote:Suppose I have a bowling ball with a diameter of 25 centimeters. What is the largest mass it can have such that it floats in corn syrup (specific gravity = 1.4)?

Last edited by UTF-8 U+6211 U+662F on May 10th, 2018, 7:11 pm, edited 1 time in total.

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