I uploaded image of the problem at the prtsc link : Screenshot by Lightshot

I only know that Angular velocity w at link A cannot have a component along the y-axis so w * j = 0.

Please guys help me, beer is on me :D ]]>

*I am just not sure what formula to even use for this. PLEASE help. This is a study guide question, not for an actual grade...but I NEED to know how to do it. ]]>

I need a reliable link to proof someone that distance doesn't depend on a reference frame in Euclidean space.

For example: if there are two points on the Earth the distance is the same no matter if we use parallels and meridians as coordinates or Cartesian coordinates, associated with the centre of the Earth.

I have such links, but in other language. I need them in English, but can't find. Please help me.

Thanks in advance. ]]>

consider these two scenarios

Scenario A-

Suppose there was a bus, and the bus has a regular size boxing glove on the front of it. And the bus is driven at whatever speed, and it hits a ball. And it hits it with a force greater than what somebody can achieve by just throwing a punch.

Scenario B-

Suppose there was a bus, going the same speed as in scenario A, but with no boxing glove on the front, and the bus has a person strapped on the front, and the person has a boxing glove, and punches the ball.

The question is,

will the ball go further in scenario A, or scenario B?

I'm not sure because I wonder if the arm is going to absorb more than it adds? ]]>

explain why large, thick tires are used more often on heavy-load-bearing trucks (or mountain bikes)

whereas smaller wheel and thinner tires are better for sports cars (or road bikes). For concreteness,

you might compare a wheel with an 30 cm Al rim and 10 cm rubber tire to a wheel with 25 cm

Al rim and 4 cm tire. As an estimate, that you may improve upon with your own research, you

may use that the density of aluminum (a common choice for wheel rim) is ρAl ≃ 2.7 g/cm3 and

its Young’s modulus is YAl ≃ 70 GPa, whereas for generic rubber the density is ρ <∼ 1 g/cm3 and

Y <∼ 0.1 GPa. (For very large construction vehicles, the rubber is considerably reinforced, but this

does not change the reasoning.) ]]>

In the image that I clipped onto this thread I have a hard time understanding the last part where mb= (0.5kg) (7/3-1). Where does the -1 come from and why does it go in the parentheses with the 7/3. I understand how to get to (0.5kg)(7/3)=(0.5kg + mb) but how does that turn into the last part of the problem? Please I need help

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I am working on a question involving the attached system.

I need to find the head required for the pump and its power requirement assuming 70% efficiency.

I have the following given information:

Pipe Area = 0.00636m^3. Flow(Q)= 0.01m^3/s Average Velocity = 1.57m/s Density of Fluid = 960kg/m^-3. Liquid viscosity = 0.081 Pa/s

I have calculated the head losses using firstly the Equivalent Head (Hm) to be 1.03m and Number Velocity head (Hf) to be 0.54m.

I think I need to use Bernoulli's to work out the power, however I don't fully understand its use and have found several different Power outputs.

Im currently sat with the answer as 2.2Kw.

I have added the height to combat as 15m + 1.57 (total losses)

P2 I have 200000pa/(960x9.81)

This works out as P1 = 356Kpa

Im not sure if this is correct and how to get this into pump power.

Thanks

http://www.7supplements.org/embova-rx/ ]]>

A student is throwing bricks at his physics teacher. The bricks have a mass of 2 kg and the student can throw them with a speed of 10 m/s. The teacher is standing on a frozen lake so there is no friction and his mass is 86 kg.

a) The teacher catches the first brick. How much kinetic energy did he absorb? How fast is he traveling?

Answer: 97.25 J, 0.227 m/s

b) The teacher deftly blocks the second brick with his forehead, resulting in the brick bouncing back toward the student at 2 m/s. What is his velocity after this collision? Remember he is still holding the first brick!

Answer: 0.5 m/s [away from student]

c) The teacher catches one more brick. What's his velocity?

Answer: 0.71 m/s [away from student]

d) The teacher wants to get away, so he decides to throw bricks back towards the student. He can throw the bricks at 15 m/s (relative to himself). but he can't decide whether it would be better to throw them all at once, or one after the other. Determine which scenario would produce a higher final speed.

Answer: 1.378 m/s vs. 1.385 m/s respectively.

Please help me understand what I'm supposed to do for d). For throwing them all at once I tried:

(90kg)(0.71m/s) = 86vf + (4kg)(-15m/s)

(90kg)(0.71m/s) + (4kg)(-15ms) = 86vf

(86kg)(0.71m/s) + (4kg)(-15ms) = 86vf

...and a million other combinations. Needless to say, none of them have worked and I can't understand momentum. Thanks for any help. ]]>

Here it is : we let a dye diffuses into an environment of dimension L. We inject that dye into a box by one face, at t = 0 on x = 0.

The linear density c follows that equation :

∂c/∂t = D [∂²c/∂x²]

the conditions are :

c(x, t = 0) = 0 (for x ≠ 0)

Integral from x=0 to L of c(x,t)dx = m0

The questions are

1/ nondimensionalize the equations and the conditions,

2/ to reveal a term homogeneous to a time, then what is its signification

3/ compare the characteristic lengths of the two equations systems.

I think I'm wrong but when nondimensionalizing the equation I found :

(∂²c ̃)/(∂²t ̃ )-(∂²c ̃)/(∂x ̃²)=0

Thanks a lot for your help ! ]]>