Initial Definition and 1000 Threads

with the initial concentrations: [A] = 0.000500 M, [B] = 0.000698 M, with the initial concentrations: [A] = 0.000500 M, [B] = 0.000698 M, and [C] = 0 M, find the value of K if [C] = 0.0000866 M at equilibrium. K = [C]/([A]*[B]) just want to check my answer of 344, seems wrong to me

So when you calculate the scattered electron energy and the scattered photon energy (for 180 degree deflection) you get roughly the following (in keV). Photon(in)__Photon(scattered)__Electron(recoil) 27.5_______24.8______________2.7 81_________62_______________19...

Homework Statement The question is solve using laplace transforms: y" - 4y = 1-2t where y(0) =0 and y'(0) = 0 Ans is: y = t/2 - 1/4 + 1/4*e^(-2t) Homework Equations http://www.stanford.edu/~boyd/ee102/laplace-table.pdf" partial fractionsThe Attempt at a Solution (s^2)Y - sy(0) - y'(0) - 4Y =...

A ball is launched directly upward from ground level with an initial speed of 18 m/s. (Air resistance is negligible.) What equation would I use to find the time the ball was in the air?

dy/dt = 2y-5, y(0) = y_0 The answer I got for this was y =5/2 + (y_0-5/2)e^t but the solution is y =5/2 + (y_0-5/2)e^-2t Where did this -2t come from? My steps: dy = (2y-5)dt Integrating both sides gives 1/2*ln|2y - 5| = t + C take exp of both sides gives 1/2(2y-5) = Cet...

dy/dt = y-5 , y(0) = y0 The general form for first ODE has to resemble this dy/dt + p(t) = g(t) so I moved the y over to the left side of the equation dy/dt - y = -5 I think this is where I screw things up. It's not really in this form dy/dt + p(t) = g(t) but rather dy/dt - p(t)...

Homework Statement A dynamite blast at a quarry launches a chunk of rock straight upward, and 2.1 s later it is rising at a speed of 19 m/s. Assuming air resistance has no effect on the rock, calculate its speed at (a) at launch and (b) 5.2 s after the launch. Homework Equations v = v0 +...

QUESTION: Solve the separable differential equation dy/dx = sqrt(4y+64), Initial Condition: y(4)=9, and find the particular solution satisfying the initial condition. MY ATTEMPT: (dy/dx)^2 = 4y+64 ((dy/dx)^2)-4y = 64 ,/' (((dy/dx)^2)-4y) dx = ,/' 64 dx Is this the right method...

Homework Statement A ball is thrown downward with an initial speed if 20 m/s on earth. What is the acceleration of the ball? Homework Equations vf=a (change in time)t + vi The Attempt at a Solution well you have to find the velocity of then find acceleration. and acceleration is...

Homework Statement The equation 2y'' - y' + y^2(1-y) = 0 is a special case of an equation used as a model for nerve conduction, and describes the shape of a wave of electrical activity transmitted along a nerve fibre. Find a value of the constant a so that y = (1 + e^(ax))^(-1) is a...

Homework Statement Solve each of the following initial value problems: a) f'(x)=(x2-1)/x5 f(1/2)=3 Homework Equations The Attempt at a Solution I guess my problem with this is I'm not 100% sure what I'm being asked to do. I know I need to use integration to find the original...

Homework Statement Find the position function with the given initial position. v(t) = 5t1/3 s(0)=5 Homework Equations The Attempt at a Solution Find the anti derivative 15/4t4/3 + c s(0) = 15/4t4/3 + c 5 = 0 + c I'm assuming since s(0) = 5 I...

Homework Statement I'm having trouble solving the following exercise: Given the following wave equation: y=0.01cos(wt-kx)+0.02*6^(1/2)sin(wt-kx) prove that if w=16s^-1 and k=6m^-1 then the amplitude of the wave is 0.05 meters and the initial phase is -pi/4 how can I prove that? By phasor...

Hello, everybody! During the whole of my undergraduate study of physics, this one thing always bothered me. It concerns the interplay of conserved quantities, symmetries, Noether's theorem and initial conditions. For a system of N degrees of freedom, governed by the usual Newton's laws...

Homework Statement Find v(t) across a cap. in a series rlc circuit with no driving force (initial v across cap: 24V) Homework Equations from the values of the components, \alpha > \omega_0, the circuit is overdamped, and the following equation can be used: v(t) =A_1 e^{s_1 t} + A_2...

I have just started a calculus book, and I can't figure out how to solve this problem: Homework Statement The landing velocity of an airplane (i.e., the velocity at which it touches the ground) is 100 mi/hr. It decelerates at a constant rate and comes to a stop after traveling 1/4 mile...

Hello, world :) My first post here. I have to choose a topic for a project in astrophysics. I intend to major in astronomy and it's my first year of studies, so I don't have much knowledge so far, though I don't mind picking a 'heavy' topic for this assignment - I know I'll benefit from...

Hello, I was wondering if anyone could help me with deriving the volume created by the rotation of a polar equation around the initial line. So, I thought about adding the surface area of cones (multiplied by d\theta) if each cone the triangle created with s-length of f(\theta) and r-length...

I need help! I have a 426g block on a frictionless ramp with initial height, h. The ramp curves, where the height is 2.6 meters before it flies off. I need to know the initial height, can someone please help? :smile:

Homework Statement Solve the following initial value problem y^{''} + 2y^{'} - 15y = 4\delta(t-2), \quad y(0) = 1, \quad y'(0) = -1. Homework Equations The Attempt at a Solution See figure attached for my attempt at the solution. Does anyone see any problems? Sorry if...

Hi, I've seen many variations of explanations of the twin paradox using special relativity, but i haven't yet seen an explanation that bothers to take into account the initial acceleration of the traveling twin away from planet Earth. Is it safe to say that this can be neglected...

I've been trying to work through the heat equation given in this Sous Vide cooking primer: http://amath.colorado.edu/~baldwind/sous-vide.html It gives a modified version of the heat equation with a shape parameter for simplification. The equations are shown below...

Homework Statement An athlete executing a long jump leaves the ground at a 31.6° angle and travels 7.78 m. What was the take-off speed? I have tried to solve this question but somehow keep arriving at the wrong answer. The formula that I derived is : distance=V(initial)*sin^2(theta)/g...

Hi guys I have two points A and B (in 2 dimensions) and want to use runge kutta 4th order to give me points between these two points starting from A __> B (NOT B___> A). How can I choose the initial point then. Cheers,:smile:

A basketball player makes a shot from a height of 2.50 m at an angle of 30 degrees above the horizontal. The horizontal distance between the player and the hoop is 6.00 m. The hoop is 3.00m above the ground. Find the magnitude of the initial velocity of the ball which will cause it to go...

I was wondering if it were in actuality possible to assume the universe was created from a big bang, as it seems we used current understanding of the laws of physics as they apply to us now, and extrapolated back. Could it be possible that the boundary conditions we form our laws of physics upon...

Homework Statement I've been given equations that have derivatives as initial conditions, rather than things like u(0,t)=u(L,t)=0 Things like this: http://img444.imageshack.us/img444/5082/mathu.th.jpg Uploaded with ImageShack.us Homework Equations The Attempt at a...

Hi all! I have quiet a lot a problems solving and programing with Mathematica this system of diff. equations: y'[x] == 1/b[x], b'[x] == 1/ubb 1/(y[x] + R1) 1/b[x] (uba 1/(y[x] + R1) - ub), b[0] == b00, y[0] == 0 y[2] == Sqrt[5] where ubb, uba, ub are functions: ub = b[x] -...

A spring gun has a spring with a constant of 2.0 N/cm. If the spring is compressed 3.0cm and the gun is loaded with a .15 kg ball, what will be the initial velocity? Equations such as E(k subscript)=0.5mv^2 E(p subscript)-mgh [b]3. i think that since...

Homework Statement It gives the mass, energy gained (change in energy), initial velocity and power and time I　need to find final velocity Homework Equations EK= 0.5mv^2 The Attempt at a Solution I was thinking of plug in the number into above formula but if i do this i won't be...

Homework Statement This is a 2 part question and I already solved for part I. Part II is what I don't get. a) A 3.16 g object moving to the right at 24.3 cm/s makes an elastic head-on-collision with a 6.32 g object that is initially at rest. The acceleration of gravity is 9.8 m/s2 . 24.3 cm/s...

Homework Statement For the following problem: A piece of balsa wood with density .50 g/cm^3 is released under water. What is its initial acceleration? I have gotten this far: Fnet=Fbuoy-mg -ma=p(water)gV(displaced)- p(wood)g(Vdisplaced) =(p(water)-p(wood))gV=-ma where p="rho" But in this...

Homework Statement A rotation wheel required 3.0 s to complete 37 revolutions. its angular speed at the end of the 3.0 s interval is 98 rad/s. what was the original angular speed of the wheel? Homework Equations average omega = change in angle/change in time The Attempt at a...

Homework Statement Hello I am asked to find the solution to the following equation no infinite series solutions allowed. We are given that there is a string of length 4 with the following... ytt=yxx With y(0,t) = 0 y(4,t) = 0 y(x,0) = 0 yt(x,0) = x from [0,2] and (4-x) from [2,4]. Homework...

Homework Statement A police officer arrives at the scene of a collision of the two snowmobiles to find both drivers unconscious. When two vehicles collided, their skis became entangled and the two snowmobiles remained locked together as they skidded to a stop. One driver was thrown clear of...

Hey everyone; I am a grade 12 student and I am totally stuck on this question and would appreciate your help. I don't want just the answer, I need help with the steps so that I understand how to do this type of problem. Here's the question: A police officer arrives at the...

Hi, we can determine the velocity to hit x and y point with angle of projection given. but can we do the same if the initial height of projection is given?

Homework Statement dy/dx=5y(1-y) y(0)=0.1 x belongs to [0; 2] Homework Equations The Attempt at a Solution dy/5y(1-y)=dx using partial fractions (1/(-y^2+y))=1/(y(1-y))= A/y+B/1-y multiplying both sides by (y(1-y)) gives 1=A(1-y)+B(y) when y=0 1=A so A=1 when y=1...

why doesn't the vertical distance traveled in the given time ,under the action of gravity alone, below the straight line it would follow in the absence of gravity, depend upon the angle of projection of a projectile? With no gravity, the projectile, which is projected at an angle at certain...

1. Homework Statement Two asteroids of 1.0x107kg and 6.0x107kg respectively, are initially at rest in interstellar space separated by a large distance. Thier mutual gravitational attraction then causes then to fall toward each other on a straight line. Assume the asteroids are spheres of...

Homework Statement Someone throws a rubber ball vertically upward from the roof of a building 8.00 m in height. The ball rises, then falls. It misses the edge of the roof, and strikes the ground. If the ball is in the air for 3.00 s, what was its initial velocity? (Disregard air resistance...

I'm reading Roger Penrose's Cycles of Time. On p. 124 he's explaining why he thinks inflation doesn't solve the mystery of why the universe started out in a low-entropy state. He argues that a high-entropy collapsing FLRW universe would consist of "a horrendous mess of congealing black holes,"...

Homework Statement Johnny jumps off a swing, lands sitting down on a grassy 20 degree slope, and slides 3.5m down the slope before stopping. The coefficient of kinetic friction between grass and the seat of Johnny's pants is 0.5 What was his initial speed on the grass?

Homework Statement Y' + 8y = e^-2t*sint, with initial condition y(0) = 0 Homework Equations L{e^(-2t)sin(t)} = 1/((s+2)²+1) The Attempt at a Solution Alright so I've been working on this one for about an hour, I really don't know why but I'm having major problems with these types...

Y' + 8y = e^-2t*sint, with initial condition y(0) = 0 Alright so I've been working on this one for about an hour, I really don't know why but I'm having major problems with these types of problems, whether i don't understand how to set it up or I don't understand partial fraction...

Homework Statement Solve the initial value problem Given: x=0, y=-2Homework Equations 2x(y+1)dx - ydy = 0The Attempt at a Solution Manipulating the given equation: --> 2x(y+1)dx - ydy = 0 --> 2xdx = ydy/(y+1) --> 2xdx = (1 - 1/y+1)dy --> 2x2/2 = y - ln(y+1) + lnC (where lnC is a constant)...

Its been argued that inflation needs the initial conditions to be finely tuned: eg: http://en.wikipedia.org/wiki/Inflation_(cosmology)#Fine-tuning_problem does this paper resolve this problem...

The radius of Mercury (from the center to just above the atmosphere) is 2440 km (2440x10^3 m), and its mass is 0.3x10^24 kg. An object is launched straight up from just above the atmosphere of Mercury. (a) What initial speed is needed so that when the object is far from Mercury its final...

Homework Statement A person wants to shoot a rocket off of a mountain 3.70 km high so that the rocket, when shot at 37.7° above the horizontal from the very top of the mountain, lands at the foot of the mountain 9.65 km (horizontal distance) away. What initial speed must the rocket have...

Homework Statement An Olympic basketball player shoots towards a basket that is 5.52 m horizontally from her and 3.05 m above the floor. The ball leaves her hand 1.52 m above the floor at an angle of 32.0o above the horizontal. What initial speed should she give the ball so that it reaches the...