Initial Definition and 1000 Threads

Hey, I need some guidance on an IVP. In general, how do you proceed on these types of problems when you have only the initial values but no initial equation? For example, I have x1(0)=1 and x2(0)=0 but that is it. I understand, for example, how to do IVP's in the context of separating...

Hello, I have a problem which asks what is va, dva/dt, and d2va/dt. I've been working on it for hours and have only been able to find out va which equals zero. Apparently dva/dt equals (V/L)sqrt(M/C) but I'm not sure how they got this. I was able to find out values of things like the...

Hi, How can I solve the diffusion equation in one dimension: u_t=ku_{xx} ; -\infty < t < \infty , 0<x<\infty With the boundary conditions: u(0,t)= T_0 +Acos(wt) u(x\rightarrow \infty,t) \rightarrow T_0 Thanks!

Homework Statement solve the initial value problem for u du/dt= (2t + sec^2(t))/2u also, u(0)=4 Homework Equations antiderivative of sec^2(t) is tan(t) + C The Attempt at a Solution So, the first thing i did was move the "u" with the "u" and "t" with the "t". so the equation looks like...

Homework Statement What is the motion of a body thrown upwards from the Earth's surface, with escape velocity as it's initial velocity. Disregard the air resistance. Homework Equations v_e = \sqrt{\frac{2 G M}{x}} F_g = \frac{G M m}{x^2} The Attempt at a Solution I though this...

Homework Statement A truck drives in a straight line, east, from point A to point B, a distance of 180 meters, during 10 seconds, while slowing down at a constant rate of 6 meter per second squared. Calculate the initial velocity. The Attempt at a Solution Attached. I don't think...

Homework Statement I've attached the actual document containing the question in case anyone needs more information. I have it all pretty much figured out, except how to interpret one of the initial condition equations (top of second page): q(t) = dT/dx (x=0,t) Which as I read it...

Hi First of all, this is not a homework question, but I'm sorry if it's in the wrong sub-forum. I know that a football (soccer) has been kicked a distance of 5 meters using 0,16 seconds, that would give an average speed of 112,5 km/h, or approx 31 m/s. But since the speed of a football is...

Homework Statement A deer jumped out at 40 m in front of a car traveling at 30 mph. If the car managed to stop with 10 m to spare. Determine the velocity at which the car would be traveling so that the collision could not be avoided. Homework Equations Vf2=Vi2+2*AD Vf=Vi+At...

?!??Find an initial velocity v such that there's no oscillation,is my solution correct Homework Statement Can somone kindly tell me if my solution to question C and D is correct, if not, what did i do wrong? http://img9.imageshack.us/img9/4914/b52009cd.gif Homework Equations The Attempt at...

if a ball is thrown and caught at the same height with constant horizontal velocity and no vertical displacement is its initial and final velocity the same? since v2y^2=v1y^2+2aDy, no displacement means final vertical velocity will be the same as initial, since v2x=v1x, horizontal velocity...

Homework Statement a ball that is 10cm in diameter is thrown 2.4m above the level of hands vertically to reach a ceiling what is the initial velocity Homework Equations struggling to determine the intial velocity as have no time The Attempt at a Solution Help! really struggling

How big is the initial size of the Big Bang... inside a Planck length? Can it fit inside? Or as big as an egg? Or a kilometer?

Homework Statement A 7 kg shot put is thrown 18 meters. What was its minimun intial energy? Homework Equations When θ = 45° Range = V0sin(2θ)/g Velocity = √(R * g)

I have seen lots of simulations using the shallow water equations, and every one I've seen involves having some sort of initial displacement in the water, resulting in a propagation of waves through a medium of either constant or variable depth, as a function of position. However, can you...

Homework Statement A 5000-kg freight car rolls along rails with negligible friction. The car is brought to rest by a combination of two coiled springs as illustrated in the figure below. Both springs are described by Hooke's law and have spring constants with k1 = 1500 N/m and k2 = 3700 N/m...

I am working on the following initial value problem: y'' + 4y = 4, y(0) = 1, y'(0) = 1 The method they show is: (1): y = A cos x + B sin x A = 1, (2): y = 1 + A cos x + B sin x y(0) = 1 + A = 0 y'(0) = B = 1 Final answer is y(x) = 1 + sin(x) The problem I don't see is the first...

Homework Statement dx/ dt = x + y dy/ dt = x + y + et x(0) = 0 y(0) = 1.Homework Equations The Attempt at a Solutionx'' = x' + y' = x' + x + y + et x'' - 2x' = 0 y = x' - x

Homework Statement Conditions: (ii)x0 =0 and v0 =20ms−1 with a mass of 1 kg with c1 = 0.2kgs−1 and c2 = 0.02kgm−1 projectile is fired directly up (only considering motion in the EDIT y direction (previously x by mistake)) at 20m/s given eqn can calculate acceleration at the n+1 term (i.e 1...

Homework Statement A particle with a charge of 3.0 µC is located at rest 5.0 meters from a proton. a) Determine the magnitude of the electric field at the proton's location created by the 3.0 µC charge. b) Determine the initial acceleration of the proton after it is released from rest...

I was solving a projectile motion problem and was wondering if, while going downwards, an object's final y velocity can be less than the initial y velocity. If this is true, would this change the time until it hit the ground? The only reason I was thinking about this is because if x/v = t. If...

Homework Statement A body has a constant acceleration of +5 ft/s^2, an initial speed of -10 ft/s, and a time travel of 4 seconds. A)Find the total distance covered B)Find the time at which the body has an instantaneous speed of zero Homework Equations speed=distance/time...

i can't see how they got X and Y expressions V_x is the derivative of X(t) by t 'A' and phi are needed to be found but when i don't know how to innpur the initial condition to find A_x and A_y because when we integrate x' expression bot sides i get x(t)-x(0)=[A_x*cos(wt+phi)]/w -...

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...

1. For stellar objects, M>0.08, then at the epoch of star formation: What fraction of stars are Type-II supernova progenitors (M>8)? What is the fraction of the mass of stars that are Type-II supernova progenitors (M>8)? What is the fraction of the light from stars that are Type-II supernova...

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) = vyot + (1/2)g(t^2) Change in...

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...