Thanks for following up :). Yes, I was confused at where the integral c=∫vf(v)dv was coming from (I don't like using random equations which I don't know where they came from) but I figured out it was pretty much just a definition.
Hi,
I am having trouble with this concept...
"A mean speed (c) is calculated by multiplying each speed by the fraction of molecules that have that speed, and then adding all the products together. When the speed varies over a continuous range, the sum is replaced by an integral. To employ...
Homework Statement
Find (\frac{dV}{dp})_{n,T} for the Van de Waals gas law
Homework Equations
Van de Waals gas law: (\frac{p+an^2}{V^2})(V-nb)=nRT
The Attempt at a Solution
I just started doing problems like these so I would like to know if I am doing them right...
What I did was I took...
Homework Statement
A force F is used to raise a 4-kg mass M from the ground to a height of 5 m. What is the work done by the force F? (Note: sin60 = 0.87; cos60 = 0.5. Ignore friction and the weights of the pulleys.)
A) 50 J
B) 100 J
C) 174 J
D) 200 J
Please click here for picture.
Homework...
Homework Statement
Two adjacent allowed energies of an electron in a one-dimensional box are 2.0 eV and 4.5 eV. What is the length of the box?
Homework Equations
E_n=\frac{h^2n^2}{8mL^2}
The Attempt at a Solution
My question is, since E_n and n^2 are both on separate sides of the equation...
Hi,
My textbook describes Compton scattering the following way:
"...an x-ray photon...has a collision with a slow moving electron...the photon transfers energy and momentum to the electron [and recoils]..."
Is it not true that by definition when a photon collides with a particle it...
So I can't use I^2R, because by definition the current would also be a different value for a new R? But we know the voltage will stay the same for a new R, so we can use V^2/R?
Homework Statement
The average power dissipated by a resistor is 4.0 W. What is the average power if the resistance R is doubled?
Homework Equations
P_{rms}=I_{rms}^2R=I_{rms}V_{rms}=\frac{V_{rms}^2}{R}
The Attempt at a Solution
I am told the answer is 2.0 W. But here's what I am confused...
Homework Statement
The voltage across a 60μF capacitor is described by the equation vC =(18 V) cos(200t), where t is in seconds.
What is the voltage across the capacitor at t =0.010 s?
Homework Equations
N/A
The Attempt at a Solution
When you use degrees the answer is 18V and...
If I is the same for both resistors then according to P=I^2(R), R for the 60 W bulb must be higher.
But I am confused because according to P = V^2/R the 60 W has a higher R...how do I know which equation to use?
Homework Statement
Normally, household lightbulbs are connected in parallel to a power supply. Suppose a 40 W and a 60 W lightbulb are, instead, connected in series. (see here) Which bulb is brighter?
Homework Equations
P_{resistor}=I\Delta V=I^2R =\frac{(\Delta V)^2}{R}
The Attempt at a...
So if I'm not mistaken you can some them,
\Sigma R = R_{muscle} + R_{fat}
I think I can see why it would decrease now; just because more fat is being added doesn't make resistivity a bigger number. Fat was already present so the only number changing was A.
Thanks guys.
Homework Statement
A person gains weight by adding fat - and therefore adding girth - to his body and his limbs, with the amount of muscle remaining constant. How will this affect the electrical resistance of his limbs?
a. the resistance will stay the same
b. the resistance will...
Oh you're right, sorry. Yeah they are circular pipes but I just wrote down the area incorrectly. I wrote down the pipes' radii for their area when I shouldn't wrote their radii^2*pi. Thanks for the help!
Hi,
I am working on this water pressure problem,
given:
v_A = 2.0 \frac{m}{s}
gauge pressure_A = 50 kPa
the view is from above, no height changes
find: gauge pressure @ B
so,
A_Av_A=2(A_Bv_B)
1.5*10^{-2}m^2(2.0\frac{m}{s})=2(5*10^{-3}m^2v_B)
v_B=9.0\frac{m}{s}
Bernoulli's equation (w/o...
Hi,
I am trying to figure out heat engines. I don't understand why heat from a hot reservoir MUST exhaust heat into a cold reservoir. How does that satisfy the second law of thermodynamics? Why can't all energy from the hot reservoir be used to do work?
Thanks
Homework Statement
A 1.5 kg mass slides across a horizontal, frictionless surface at a speed of 2.0 m/s until it collides with and sticks to the free end of a spring with spring constant 50 N/m. The spring's other end is anchored to the wall. How far has the spring compressed when the mass, at...