Initial Definition and 1000 Threads

Homework Statement A small rock is thrown vertically upward with a speed of 17.0m/s from the edge of the roof of a 30.0m tall building. The rock doesn't hit the building on its way back down and lands in the street below. Air resistance can be neglected. Homework Equations Acceleration...

I've tried a few different equations but I'm not sure how to start this problem. I just realized I'm looking for the initial velocity since the speed of the ball is constant. A bowling ball traveling with constant speed hits the pins at the end of a bowling lane 16.5 m long. The bowler hears...

Problem: Find the solution to the initial Value problem (differential equations)? y'=-y+e^-2x y(0) = 3 Attempt: y' -y = e^(-2x) ----- (1) Linear equation of first order of form y' + y p(x) = q(x) p(x)= -1 q(x) = e^(-2x) Find the integrating factor e^∫p(x) dx = e^∫ - dx = e^-x Multiply...

I have read the time line several times for the BB: http://en.wikipedia.org/wiki/Timeline_of_the_Big_Bang And I am unclear what were the initial ingredients at or before the 10-43 seconds. All I can get from this is high temperature which means high energy or high vibrational energy in...

Projectile Motion without Initial Velocity (Only time and angle given) Homework Statement A projectile is launched at an angle of 50° above the horizontal and it hits the ground in 12 seconds. a. Calculate the maximum height of the projectile. b. Find the range of the projectile...

... factoring in fluid dynamics, not just Newtonian physics... At a given height, the object will possesses 75% of the kinetic energy of when it initially began moving. Mass is irrelevant. Given variables: -Drag coefficient -Fluid density -Cross-sectioned area -Displacement -Initial and final...

[b]1. An electron in the cathode ray tube of a television set enters a region where it accelerates uniformly from a speed of 62300 m/s to a speed of 3.86 × 106 m/s in a distance of 3.17 cm. What is its acceleration? [b]2. a = [Vf2 - Vi2] / [2d] [b]3. a = [(3.86 × 106)m/s2 - 62300m/s2]...

Homework Statement A projectile is fired through the air. It is launched from the ground, and travels without interference from wind or air resistance, landing on a raised platform above the field. Initial speed vs. final speed: Initial vertical velocity vs. final vertical velocity...

Homework problem: For the wave equation: Utt-Uxx=0, t>0, xER u(x,0)= 1, |x|<1 0, |x|>1 sketch the solution u as a function of x at t= 1/2, 1, 2, and 3 I am able to use d'Alemberts and solve for u however the boundaries and the odd/even reflections are throwing me off and...

Homework Statement A man jumps from a building into a safety net located at 11m below, that acts like a rigid body when the man hits it. Find the speed. The safety net moving 1.5m meters down stops the man completely. Find the deceleration, assumed as constant.Homework Equations Vf2= Vi2+ 2ad...

Solve the initial value problem y'=2t(1+y), y(0)=0 by the method of successive approximations. I don't know how to do this problem but I think there's integral involved in it. Please help me. Thanks.

[b]1. Check that y(t)=1/λ ∫_0-t_〖f(s) *sin(λ(t-s) )ds〗 is the solution of the following initial value problem y''(t)+λ^2y(t)=f(t), λ>0, y(0)=0,y'(0)=0 Homework Equations [b]3. I tried to do integration by parts on y(t), but...

Homework Statement (this is translated from Italian so it might have some technical mistakes :) ) A target with negligible dimensions is placed at H = 5m from the ground; a vehicle on the ground is moving at a velocity V = 2m/s (the module) and is getting closer to the target. Consider O the...

Suppose we have two sticks held in a vertical plane, pivoted at one point (check the diagram). If we let go, why is the initial acceleration of the center of the mass not equal to g? Why does the pivot exert some force at the beginning? By contrast, if we keep the sticks in a horizontal...

Homework Statement A car traveling at 88ft/s skids 176ft after its brakes are applied. The deceleration provided by the braking system is constant. What is its value? The Attempt at a Solution $$ v_0=88 \\ v_f=0 \\ d_0=0 \\ d_f=176 $$ $$ d(t)=\int88\,dt \\ d(t)=88t+c...

How to minimise this function and get initial conditions . I have the answer for initial conditions. ra = min(00237 − 0000175v + 8.693f − 000159y) subjected to 124.53 ≤ v ≤ 167.03 0.025 ≤ f ≤ 0.083 6.2 ≤ y ≤ 14.8 v= 144.2 , f = 0.025, y = 9.5 How to get this?

Homework Statement The nuclide (32,15)P undergoes Beta - decay with a half-life of 14.3 d. It is used as a tracer isotope in biochemical analysis. What is the initial decay rate of a 1.2mg sample? Homework Equations T1/2 = Ln 2 / λ Ro = λN0 The Attempt at a Solution I first...

Homework Statement For the circuit shown (in the attachment), find iL(0+) and Vc(0+). Homework Equations V=IR The Attempt at a Solution At t=0-; the inductor can be replaced by a short-circuit and the capacitor by an open circuit. This shorts out the resistor so by Ohm's law, the voltage...

Homework Statement The problem states d^2y/dt^2 +15y= cost4t + 2sin t initial conditions y(0)=y'(0)=0 Homework Equations The Attempt at a Solution All I have is this r^2+15=0 making r(+-)=√15 and making yh= C1cos√15+C2√15 the next part includes solve for...

I have a problem which in involves a second order differential equations with imaginary roots and I can seem to know how to finish the problem. d^2y/dt^2 +15y =cos 4t+2 sin t this is what I got so far r^2+15=0 for the homogeneous part r=+-(√15) Yh=C1cos√15+C2sin√15 now is...

Hello everybody, I am currently struggling with a problem that I came across while spending some free time on non-relativistic quantum mechanic problems. Suppose we have an electron that is describe at time t_0 = 0 by a wave function in position space \psi(x,y,z). Furthermore, assume...

Homework Statement (b) A particle is projected from a point O at time t = 0 and it performs simple harmonic motion with O as a centre of oscillation. The motion is of amplitude 20cm and time period 4 seconds. Find: (i) the speed of projection; (ii) the speed of particle when t = 1:5...

Homework Statement distance = 0.8meters angle = 55° gravity = 9.81m/s^2 \V_0 = ?, assuming that it leaves and falls back on the same horizontal plane. The attempt at a solution So we know for a fact that the initial velocity is supposed to be 2 m/s, according to the book at least. I tried...

Hello, I'am studying a code (called "starscream") which allows to make initial conditions (positions and velocities) for NBody simulation. They are based on Springel and White (1999) model. I have several problems about the underlying equations used in this code. Firstly, See attachment...

So I've been playing with a little N-body code in 3D for gravitational problems and have made an OpenGL visualization to go along with it. I have been generating initial conditions (positions and velocities) using explicit formulas. I was wondering of anyone knew of any resources for getting...

Homework Statement The uniform slender bar is pivoted at and swings freely in the vertical plane. If the bar is released from rest in the horizontal position, calculate the initial value of the force exerted by the bearing on the bar an instant after release. I have attached an image of...

Hello there Ladies and Gents! This question is (mostly) related to problem 10.2 in Wald which is to show that the source-free Maxwell's equations have a well posed initial value formulation in curved space-times. We start off with a globally hyperbolic space-time ##(M,g_{ab})## and a spacelike...

Homework Statement A capacitor is discharged through an 80.0 ohm resistor. The discharge current decreases to 23.0% of its initial value in 1.50ms . What is the value of the capacitor? Homework Equations t=RC The Attempt at a Solution 1500 μs = 0.23 RC RC= 6521.74 C=...

Hello! I am having trouble using the SimPowerSystems library from simulink to simulate circuits (with the powergui solver). On all the circuits I have simulated so far either of the following happens: - Adding the initial current/voltage directly at the RLC branch block culminates into...

Homework Statement A Copper wire has a shape given by a radius that increases as R(x)= aex+ b. Its initial radius is .45 mm and final radius is 9.67 mm and its horizontal length is 38 cm. Find its resistance. Homework Equations R = pL/A where p = resistivity of copper A = ∏r2 L = length of...

Hi, I have two ultrasonic transducers and a pulser-receiver(5072PR). One is the contact transducer, A120S (6MHz), from Olympus and the other is also contact mode transducer, but it is a customized ring-type transducer (2.X MHz) (like doughnut). I have two questions. First, when I turn on...

Homework Statement dy/dt=y(9-y) y(0)=2 Homework Equations The Attempt at a Solution dy/(y(9-y)) = dt ∫dy/(y(9-y)) = ∫dt partial fraction decomposition 1=A/y + B/(9-y) 1=9A-Ay +By 1/9=A 0=1/9 +B B=-1/9 1/9∫1/y -1/9∫1/(9-y)=t+C 1/9ln|y| -1/9(ln|9-y|)...

Homework Statement State what will happen when a positive particle has an initial velocity opposite to the direction of the electric field Homework Equations The Attempt at a Solution

A circus clown in a cannon is shot vertically upward with an initial speed of 18.0 m/s. after ascending 4.5 m ,she collides with and grabs a performer sitting still on a trapeze. They acend together and then fall. what is their speed when they reached the original launch height. The clown and...

calculate the initial acceleration of a 13 140 kg V-2 rocket bomb fired vertically, if the thrust of its engines is 2.63 x 10 to the power of 5 N. then calculate the rockets acceleration near "burn-out", when its mass is only 4170 kg. So i did. Part 1. Fnet = ma a = fnet/m 20.01m/s^2=...

I read in a article that Earth revolves around the sun at speed of 30km/s but from where did it get its velocity at the beginning..?

I performed a lab where we needed to find the mathematical relationship between the starting speed (initial velocity) and the stopping distance. However, I'm pretty sure we recorded all the initial speeds incorrectly. Is there a way to calculate the initial speed knowing the Distance Traveled...

Homework Statement A novice snowboarder who weighs 60kg is sliding down a 10 degree slope at a constant velocity of 8 m.s^-1. When they reach the bottom of the slope, they slow down due to the kinetic friction between the snowboard and the snow. Find the rate at which the skier is de...

A rocket, which is in deep space and initially at rest relative to an inertial reference frame, has a mass of 59.5E5 kg, of which 7.39E5 kg is fuel. The rocket engine is then fired for 300 s, during which fuel is consumed at the rate of 480 kg/s. The speed of the exhaust products relative to the...

I have been working this one all day. No luck as far. The question: A projectile is launched at an angle of 53.1° with respect to the horizontal, as shown in Figure 2-34. ( Ill try to give you a picture of example 2-34) It strikes a target that is 120m away horizontally and 160m below the...

Homework Statement Consider the Hamiltonian H=0.5p^2+ 0.5x^2, which at t=0 is described by: ψ(x,0)= 1/sqrt(8*pi) θ1(x) + 1/sqrt(18pi) θ2(x), where: θ1= exp(-x^2/2); θ2=(1-2x^2)*exp(-x^2/2) a) Normalize the eigenfunctions and rewrite the initial state in terms of normalized...

A mass of 130 g is held by a horizontal spring constant 22 N/m. It is displaced from its equilibrium position and released from the rest. As it passes through its equilibrium position, its speed is 4.2 m/s. a) find work done on the spring. w=1/2mv^2 1/2(.13kg)(4.2)^2= 1.14 (correct) b)...

Homework Statement So I just wrote my midterm in physics, and I was curious on how to do the last question. Parallel plates, length 5.5cm, Distance between them is 0.3 cm Electric Field (E) is 5.4x10^4 Asking what is the initial speed of a proton going through the parallel plates if it just...

Here is the question: Here is a link to the question: No idea how to solve this 2nd order IVP. Please help? - Yahoo! Answers I have posted a link there to this topic so the OP can find my response.

Homework Statement Two balls are thrown vertically upward, one with an initial speed twice that of the other. The ball with the greater initial speed will reach a height - twice that of the other - 4 times that of the other Homework Equations dy = vt + 1/2 at^2 [if i use this equation, i...

x(t)=Acos(ωt+ϕ)\\ v(t)=-Aωsin(ωt+ϕ)\\ \\ Let\quad n=integer,\quad A=0.5,\quad ω=2.\\ \\ Given\quad initial\quad position\quad (0,\quad 0.25)\quad and\quad initial\quad velocity\quad (0,\quad 1),\quad find\quad ϕ.\\ \\ x(t)=0.5cos(2t+ϕ)\\ 0.25=0.5cos(ϕ)\\ ϕ=±1.0471975512+2πn\\ \\...

Homework Statement A ballistic pendulum is used to measure the speed of a bullet fired from a gun. The pendulum consists of a 20.0g block hanging from a string. A bullet, with mass 0.50gg, imbeds itself in the block causing the block to swing up to a height of 5.00cm. Find the speed of the...

Homework Statement \frac{d^2 y}{dx^2}\cdot\frac{dy}{dx}=x(x+1), \hspace{10pt} y(0)=1, \hspace{5pt} y'(0)=2 Homework Equations None I can think of... The Attempt at a Solution The only thing I even thought to try was turn it into the form: \frac{d^2 y}{dx^2}{dy}=x(x+1){dx}...

According to test performed by the manufactures, an automobile with an initial speed of 75 km/h has a stopping distance of 25 m on a level road. assuming that no skidding occurs during breaking, what is the value of μ , between the wheels and the road required to achieve the stopping distance...

In the figure, a frictionless roller coaster car of mass m = 800 kg tops the first hill with speed v0 = 18 m/s at height h = 44 m. What is the speed of the car at point B? (point B is one half the height of the top of the first hill) (1/2)mv2 Wg=mgd (1/2)(800)(182)=129600...