Homework Statement
A horizontal force fo 190N is needed to pull a 70kg box across a horizontal floor at a constant speed. What is the coefficent of friction between the box and the floor?
Homework Equations
Fnet = ma
The Attempt at a Solution
My setup is F - F_f = m*a
But I...
Homework Statement
What is the final temperature of water if 175 g steam at 150 C loses 423 KJ of energy?
Homework Equations
Q = M *C_p * Δ T
Q = m * heat of (phase_change)
The Attempt at a Solution
This is how I would go about solving this problem.
Going from steam to water requires...
Homework Statement
Prove the absorption law A U (A and B) = A
Homework Equations
The Attempt at a Solution
I need to prove the sets are equal.
I don't know how to prove the right hand as a subset of the left hand.
For left hand as subset of right hand, it's pretty simple (we can define...
Homework Statement
The book states the following:
The sample mean is defined by: \bar{x}=\sum_{i=1}^{n}x_{i}/n
The computation of the sample mean can often be simplified by noting that if for constants
a and b, y_{i}=ax_{i}+b, then the sample mean of the data set y1 , . . . , yn is...
I am a Computer Engineering major. I begin to like analyzing things (I always do). I love testing things, and I really have the patience to do analyzing things, google for answers, reading and researching for answers.
But I am not a very strong math student (pretty careless and my fundamental...
Not meant to be a homework question, but since I don't have any valid data on hands so I am hesitate posting this in classical physics forum.
The headline suggests the opposite of what we physics tell us.
But my question is, is it theoretically possible to make like poles attract (assuming no...
Homework Statement
Find the solution of the given initial value problem.
\[y''-2y'-3y=3te^{2t}\]
Homework Equations
The Attempt at a Solution
(1) the homogenous solution is given by
\[y_{h}=c_{1}e^{3t}+c_{2}e^{-t}\]
(2) the particular solution is in the form
\[y_{p}=(At+B)e^{2t}\]
(3)...
Homework Statement
Let z = 1 − i. Find z^10.
Homework Equations
The Attempt at a Solution
|z|= \sqrt{(1)^{2}+{-1}^2}
a=|z|cos(\theta ), b=|z|sin(\theta )
and we find that \theta = -pi/4 or 7*pi/4 (Accoridng to this, it is in the fourth quadrant )...
Homework Statement
Find graphically the value of x in the interval [0,2] which satisfies the equation
\frac{\mathrm{d} }{\mathrm{d} x} \left ( \frac{e^{-x^2}sin(x^{2})}{cos(x)+3} \right )=\frac{x^{2}}{10+x}
Homework Equations
Definition of limits f ' (x0) = lim x -> x0 f(x)-f(x0)/(x-x0)...
Homework Statement
White light is sent downward onto a horizontal thin film that is sandwiched between two materials. The indexes of refraction are 1.80 for the top material, 1.66 for the thin film, and 1.50 for the bottom material. The film thickness is 5.4 10-7 m.
Homework...
Homework Statement
Find the particular solution.
y(k+2) + y(k+1) -6y(k) = 3^(k)
Homework Equations
The Attempt at a Solution
Still need to be answered
Question (1): Before finding the particular solution, is it true that we should ALWAYS get the homogeneous solution...
Homework Statement
Convolution-Summation of a First Order System with Constant Coefficients
http://dl.dropbox.com/u/14655573/1.PNG [Broken]
Homework Equations
The Attempt at a Solution
The solution from the lecture
[PLAIN]http://dl.dropbox.com/u/14655573/2.PNG [Broken]...
Homework Statement
Verify that the response of the system governed by the 1st order different equation
y(k)=bu(k)+ay(k-1)
is given by this solution
y(k)=\frac{b}{1+a}\left [ (-1)^{k}+a^{k+1} \right ]
for u(k) = (-1)^k
The Attempt at a Solution
The solution said we can verify this...
Homework Statement
Determine whether this is an exact equation. If it is, find the solution.
\[\frac{\mathrm{d}y }{\mathrm{d} x} = -\frac{ax+by}{bx+cy}\]
Homework Equations
The Attempt at a Solution
If I moved the right side to the left (because an exact equation has the form...
Homework Statement
Find the solution of the given initial value problem in explicit form and determine the interval in which the solution is defined.
\[x dx+ye^{-x}dy = 0\] with initial condition y(0) = 1
Homework Equations
The Attempt at a Solution
I solved the first part...
Homework Statement
Find focal length for meniscus convex (3)
Given r = 15, and n = 1.5
Homework Equations
Lens maker's equation
The Attempt at a Solution
I can find the rest except #3 and #6 (they are opposite sign of each other)
I had (1/r1 - 1/r2) gives zero... which is wrong.....
I...
Homework Statement
\[\frac{\mathrm{dy} }{\mathrm{d} x} = \frac{x - e^{-x}}{y + e^{y}}
\]
Homework Equations
The Attempt at a Solution
This is how I did it....
[1] multiple
\[y + e^{y} (dy) = x - e^{-x} (dx)\]
[2] integrate both sides and I get
\[\frac{1}{2}y^{2} + e^{y} =...
Homework Statement
Given two isotropic point sources of sound \[s_{1}\] and \[s_{2}\]. The sources emit waves in phase at wavelength 0.50m; they are separated by D = 1.75m. If we move a sound detector along a large circle centered at the midpoint between the sources, at how many points do...
Homework Statement
[PLAIN]http://dl.dropbox.com/u/14655573/110218_203248.jpg [Broken]
Part (1)
The figure shows the output from a pressure monitor mounted at a point along the path taken by a sound wave of a single frequency traveling at 343 m/s through air with a single frequency...
Homework Statement
A regular tetrahedron has the vertices of its base A(1,1,0) B(3,1,0) C(2,1+(3^(1/2),0). Find coordinate of vertex S?
Homework Equations
The Attempt at a Solution
If this is a tetrahedron
Then we know the length by caclulating the distance formula, which gives...
Homework Statement
Two sinusoidal waves with identical wavelengths and amplitudes travel in opposite directions along a string with a speed of 10 cm/s. If the time interval between instants when the string is flat is 0.50 s, what is the wavelength of the waves?
Homework Equations
v = w/k =...
Homework Statement
In the figure it shows a pattern of resonant oscillation of a string of mass m = 2.5g, length L = 0.800m and under tension T = 325.0N. What is the wavelength of the transverse waves producing the standing-wave pattern, and what is the harmonic number n? What is the frequency...
Homework Statement
The part of the hyperboloid x^2 + y^2 - z^2 = 1 that lies to the right of the xz-plane
The Attempt at a Solution
Clearly, since it's demanded in turns of xz-plane, we have
y = sqrt( z^2 - x^2 - 1)
To parametrize it, we can simply use x = x, z = z, and y =...
Homework Statement
For two waves in superposition, we have, let say
\[y_{1} = Asin(kx-wt),
y_{2} = Asin(kx-wt+\Phi )\]
We use the trig identity sin A + sin B to simplify the combination
Whereas for standing waves, we use the trig identity sin(a +/- b) to combine the result.
As I...
Homework Statement
This is what my professor wrote on the board.
Suppose the condition is as follows
y(0) = y(L) = 0
link to img http://www.izhuk.com/painter/image2.php?id=1286387629-69-86-215-102&md5=c054d375567134a9faa133b47fe690b2
This is the fundamental harmonic - with nodes appear at x...
Homework Statement
For two variables, F = grad(f) if only if partial P / partial y is equal to partial Q / partial x
where, P and Q represent the x, y function, P(x,y) and Q(x,y)
For example:
F(x,y) = P(x,y) + Q(x,y)
Now the question is, for three variables, I have P + Q + R.
Is...
Homework Statement
Find parametric equations for the tangent line to the curve with the given parametric equations at a given point.
\[x = t^5, y = t^4, z = t^3\] at point (1,1,1)
Homework Equations
The Attempt at a Solution
So we need to have direction vector, and a point.
To find...
Homework Statement
For the circuit in the figure, determine i1to i5
http://i55.tinypic.com/dokoc5.png
Homework Equations
current division: in = (Requivalence / Rn) * itotal
Requivalence in parallel = R1*R2 / R1+R2
The Attempt at a Solution
|| (parallel), and +s (series)
1ohms ||...
Homework Statement
Here is an interesting reading to my question.
http://coraifeartaigh.wordpress.com/2010/02/27/what-is-a-field/
The author wrote:
The reason he said each charge will experience a different force is assuming different r (and not a constant r)?
Another question is to...
Homework Statement
The speed of sound in air (in meters per second) depends on temperature according to the approximate expression
v = 331.5 + 0.607T
where T is the Celsius temperature. In dry air, the temperature decreases about 1C for every 150m rise in altitude.
a. Assume this...