Initial Definition and 1000 Threads

Homework Statement What is the Initial Rate of Decomposition for NO2. Where 2NO2-----> 2NO + O2 K=.54 Concentration at t=0 is .008 M This is a second order reaction.Homework Equations Rate=k[C]2The Attempt at a Solution Rate=.54[.008]2=.000035 (directed to give a two sig fig answer) This...

In the following video Penrose states that the Universe was so special and organized at its initial state the figure describing it would be "at least" 10^123. Begin at 4:50 Has this figure or any other figure been confirmed? Where can I go to find out if this is true or not. I found...

For some of the questions questions the initial arm is in the positive x and y quadrent and the terminal arm moves counter clockwise (+)this is considered positive , for some of them it is in the negative x and positive y quadrent, how does one determine where the initial arm is to be placed...

Homework Statement a block is at the base of a ramp of angle 35degrees. The ramp is 5 m long and has a coefficient of static and kinetic friction of .6 and .2 respectively. The block is initially given a velocity of 12 m/s up the ramp, how far from the ramp will the block land? my main...

Homework Statement A baseball is hit at a 45 degree angle 1.3m above the ground. It barely clears a 3m wall 130m away. With what velocity was the ball hit? Homework Equations Equations of Motion The Attempt at a Solution So I realized that without air resistance this would be a...

A rude tourist throws a peach pit horizontally with a 7.0 m/s velocity out of an elevator cage. The ground is 17 m below. How long will it take for the pit to land if the elevator is moving upward at a constant 8.5 m/s velocity? d=Vot + 1/2at2 My attempt that continuously doesn't...

Hi all, Given an initial point (longitude and latitude), a distance, and an angle of motion (in the 2d space), how can we calculate the coordinates (longitude and latitude) of the point that lies at that distance in the direction of that angle from the initial point?

Good Afternoon, wondering if I could get some assistance. I'm not formally learning physics its just an interest I have, and try to complete problems during my spare time. I have one particuar question that I'm stumped with, so any help would be great! Q: You are asked by a film director...

Simple question hopefully. What was the initial value for the Hubble parameter immediately following the big bang (or ending of inflationary epoch)? I presume the initial velocity of expansion was lightspeed and started slowing from there.

Euler's method? Describe how to modify Euler's method to deal with the initial condition of y(5)=3 instead of y(0)=3. Use this on the equation y'=1+t using a time step of 0.1 and initial condition of y(5)=3 and find y(5.4) . ?? Now find the exact solution of this equation using calculus...

So, I do not think I did this properly, but if f(-x)=-f(x), then u(-x,0)=-u(x,0), and if g(-x)=-g(x), then ut(-x,0)=-ut(x,0). According to D`Alambert`s formula, u(x,t)=[f(x+t)+f(x-t)]/2 + 0.5∫g(s)ds (from x-t to x+t) so, u(0,t)=[f(t)+f(-t)]/2 + 0.5∫g(s)ds (from -t to t) f is odd, and so is...

Calculus of variations problem. I want to make stationary the integral of (1+yy')^2 dx from 0 to 1. I know what the Euler-Lagrange differential equation turns out to be, but how do I interpret the limits of integration as initial conditions for the diff eq? also, can i use laplace transforms to...

Homework Statement A cliff diver runs horizontally at 4.00 m/s. He hits the water 3.00 s later. Ignore air resistance. (a) What is the diver's speed (magnitude of the velocity vector) just before he hits the water? Homework Equations Change in y-component: y(t) = v[SIZE="1"]yot + (1/2)g(t^2)...

Homework Statement Coyote falling down with a parachute holding an anvil at 10m/s. At 50m he drops the anvil. A) How long does it take for the anvil to hit the ground? B) what is the velocity of the anvil right before it hits the ground? Homework Equations X= Xo + V0T+1/2A(T^2) g= 9.8...

Hello I have a question about coupled oscillators and what initial conditions affect what constants of integration. In the book I have, A.P. French Vibrations and Waves, the guesses at solutions are chosen at random and sometimes do include a phase shift, while sometimes they dont. For...

Homework Statement In a circus act, clowns are shot from a cannon at a constant speed vo = 11.1 m/s. The angle of launch may be varied. What is the maximum distance D that a clown may travel, if the landing pad is at the same height as the mouth of the cannon? Knowns: Vo=11.1 m/s x = 0 y...

Initially a 1.52 µF capacitor and a 2.63 µF capacitor are connected in parallel, with 9.80 V across their plates. The two capacitors are not connected to anything else. The connecting wires are then reversed on the terminals of one capacitor, so that the positive plate of each capacitor is...

Homework Statement y' = (2x) / (y+(x^2)y) y(0) = -2 The Attempt at a Solution I tried doing this by finding the Integrating factor and I got that to be u = -1-x^2 by using the (My - Nx) / N formula. Using this did not work out for me and I'm not seeing the other approach...

Homework Statement A 3.55 kg object sliding on a frictionless surface breaks into two masses that are both equal to half of the original mass. The velocities of the masses are 3.26 m/s due north and 4.58 m/s, 25.4° north of east. Determine the original speed of the 3.55 kg mass. Homework...

Homework Statement I have three capacitors and a resistor in a closed circuit. I'm given the values of C: 15,20,10pF. They are all in series. The magnitude of each is 3.5nC. Homework Equations t = -RC ln(q/Q0) I = -Qo/RC e^(-t/RC) The Attempt at a Solution i've tried finding time first...

Homework Statement d2y/dx2 = 2-6x Given: y(0)=-3 and y'(0)=4 Homework Equations None that I know of. The Attempt at a Solution I know that for a single order derivative you would just find the integral, set y=1 and x=0. But I'm confused because here we're given two...

Homework Statement You throw a snowball from a height of 11m at an angle of 25 degrees to the horizontal to hit your teacher in the chest (1.5m from the ground) who is on the sidewalk 37m from you horizontally, at what velocity must you throw the snowball to hit your teacher Homework...

Hi, everyone: I am reading an article on the Reidemeister-Schreier method for finding a presentation of a subgroup H of a group G, given a presentation for G , in which this statement is made: A Schreier transversal of a subgroup H of F, free with basis X, is a subset T of F such...

Homework Statement A rocket is shot off a 3220 M high mountian at an angle of 35.3 to the horizontal. The rocket lands 9580 m away from the mountian, what was the initial velocity? Homework Equations y=Vi(y) *t +1/2gt^2 x= t*Vi(x) Vi(y)= sin 35.3 Vi Vi(x)= cos 35.3 Vi The...

Homework Statement OK, here's the problem: A ball (first ball) is dropped from rest from a height 20.0m above the ground. Another ball is thrown (second ball) vertically upward from the ground at the instant the first ball is released. Determine the intial speed of the second ball if the two...

Homework Statement A Circus performer is shot our of a cannon and shot over a net that is placed horizontally 6 meters from the cannon. When the cannon is aimed at an angle of 40 degrees above the horizontal, the performer is moving in the horizontal direction and just barely clears the net...

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: