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.

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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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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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.

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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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.