# Search results

1. ### Matlab Problem: Runge-Kutta Fehlberg

Homework Statement I need to write a Matlab program that solves the following: Use the Runge-Kutta Fehlberg Algorithm with tolerance TOL= 10^(-4) to approximate the solution to the initial-value problem: y'=(y/t)^2 + y/t, 1<=t<=1.2, y(1)=1, with hmax=0.05 and hmin=0.02. Homework...
2. ### Quotient Rings and Homomorphisms

Homework Statement Let R and S be rings. Show that \pi:RxS->R given by \pi(r,s)=r is a surjective homomorphism whose kernel is isomorphic to S. Homework Equations The Attempt at a Solution To show that \pi is a homomorphism map, I need to show that it's closed under addition and...
3. ### Abstract Algebra: a problem about ideal

Homework Statement Let J be the set of all polynomials with zero constant term in Z[x]. (Z=integers) a.) Show that J is the principal ideal (x) in Z[x]. b.) Show that Z[x]/J consists of an infinite number of distinct cosets, one for each n\inZ. Homework Equations The Attempt at...
4. ### Proof: Natural Number

Homework Statement Show that for any natural number K, there is an n large enough so that (2^n) > K. Homework Equations The Attempt at a Solution K is a natural number -> the smallest possible K would be 0 (lower bound?) and the smallest 2^n is 1 when n = 0, and the upper bound...
5. ### Prove a+b=b+a for integers

Homework Statement Prove that for any two integers a and b, a+b=b+a. You may use the face that this holds for natural numbers. Homework Equations The Attempt at a Solution a=(x,y), b=(u,v) x,y,u,v are natural numbers a+b = (x,y)+(u,v) = (u,v)+ (x,y) = b+a I'm not sure if my...
6. ### Linear Algebra- Subspaces

Homework Statement Let S be a nonempty set and F a field. Prove that for any s_0 \in S, {f \in K(S,F): f(s_0) = 0}, is a subspace of K(S,F). K here is supposed to be a scripted F. Homework Equations The Attempt at a Solution I don't know how to approach this problem. I know the three...
7. ### Linear Algebra- Vector Spaces

Homework Statement Let V = {(a1,a2,...an): ai \in C for i = 1,2,...n}; Is V a vector space over the field of real numbers with the operations of coordinatewise addition and multiplication? Homework Equations I know that V is a vector space over C. The Attempt at a Solution I...
8. ### Frequency and Wavelength Problem

Homework Statement A 5.00-m, 0.732-kg wire is used to support two uniform 235-N posts of equal length (see figure). Assume that the wire is essentially horizontal and that the speed of sound is 344 m/s. A strong wind is blowing, causing the wire to vibrate in its 7th overtone. What are the...
9. ### Simple Harmonic Motion of a wave

I'm still a little confused about the energy approach in part (d).
10. ### Simple Harmonic Motion of a wave

for d) I'm thinking that part (a) can be found by using the energy approach because K_max = (1/2)m(v_max)^2, from v_max, you can find a_max; part (b) cannot be found by using the energy method because energy doesn't deal with what happens in the beginning and end; part (c) cannot be found using...
11. ### Don't Miss the Boat

Homework Statement While on a visit to Minnesota, you sign up to take an excursion around one of the larger lakes. When you go to the dock where the 1500-kg boat is tied, you find that the boat is bobbing up and down in the waves, executing simple harmonic motion with amplitude 20cm. The boat...
12. ### Rocket Pendulum Problem

Homework Statement A rocket is accelerating upward at 4.00 m/s^2 from the launchpad on the earth. Inside a small 1.50-kg ball hangs from the ceiling by a light 1.10-m wire. If the ball is displaced 8.50 degrees from the vertical and released, find the amplitude and period of the resulting...
13. ### Periodic Motion Problem

Homework Statement A 1.50-kg, horizontal, uniform tray is attached to a vertical ideal spring of force constant 185 N/m and a 275-g metal ball is in the tray. The spring is below the tray, so it can oscillate up-and-down. The tray is then pushed down 15.0 cm below its equilibrium point (call...
14. ### Simple Harmonic Motion of a wave

[SOLVED] Simple Harmonic Motion Homework Statement A cheerleader waves her pom-pom in simple harmonic motion with an amplitude of 18.0 cm and a frequency of 0.850 Hz. Find (a) the maximum magnitude of the acceleration and of the velocity; (b) the acceleration and speed when the pom-pom's...
15. ### Center of Gravity Problem

Homework Statement A box of negligible mass rests at the left end of a 2.00-m, 25.0-kg plank (see image). The width of the box is 75.0 cm, and sand is to be distributed uniformly throughout it. The center of gravity of the nonuniform plank is 50.0 cm from the right end. What mass of sand...
16. ### Angular Velocity and Acceleration Problem

A wheel is rotating about an axis that is in the z-direction. The angular velocity w_z is -6.00 rad/s at t=0, increases linearly with time, and is +8.00 rad/s at t =7.00s. We have taken counterclockwise rotation to be positive. a.) Is the angular acceleration during this time interval...
17. ### Working Like a Horse

Your job is to lift 30-kg crates a vertical distance of 0.90 m from the ground onto the bed of a truck. How many crates would you have to load onto the truck in one minute for the average power output you use to lift the crates to equal 0.50 hp? The equation that I used is: P_av = (delta W)/...
18. ### Fireworks Problem

The velocity at the maximum height is zero, so it's momentum at that point is zero. After it explodes: (m_1)(v_1)+(m_2)(v_2) = 0 From the problem, (1/2)(m_1 + m_2) v^2 = 860 J I'm trying to solve for v_1 and v_2. Is my second equation correct?
19. ### Fireworks Problem

Homework Statement A fireworks rocket is fired vertically upward At its maximum height of 80.0 m, it explodes and breaks into two pieces, one with mass 1.40 kg and the other with mass 0.28 kg. In the explosion, 860 J of chemical energy is converted to kinetic energy of the two fragments. (a)...
20. ### Object at rope: work to lift it

The answer in the book is 3.6 J.
21. ### Object at rope: work to lift it

I'm sorry, I meant to ask for the work done by me. So, H= height H_1 = 0 H_2 = 4m Work_total = change of potential energy = mg(H_2 - H_1) = 264.6 and W_total = W_me + mgH_1 = 264.6J W_me = 264.6 J Did I do something wrong, because it doesn't seem right.
22. ### Object at rope: work to lift it

An old oaken bucket of mass 6.75 kg hangs in a well at the end of a rope. The rope passes over a frictionless pulley at the top of the well, and you pull horizontally on the end of the rope to raise the bucket slowly a distance of 4.00 m. So far, I have: F = force exerted by me s =...
23. ### A tug-of-war on the ice

Thanks, guys! I got it! =)
24. ### A tug-of-war on the ice

It turns out that I have to use center of mass for this problem. What I have so far: (m_J)(v_J)+(m_R)(v_R)=(m_J + m_R)V_cm The thing is, I have two unknowns here: v_J and V_cm. I suppose v_J is what I'm solving for. I'm stuck.
25. ### A tug-of-war on the ice

James and Ramon are standing 20.0 m apart on the slippery surface of a frozen pond. Ramon has mass 60.0 kg and James has mass 90.0 kg. Ramon pulls on the rope to give himself a speed of 0.70 m/s. What is James's speed? From what I understand, since there is an external force due to Ramon's...
26. ### Motion in Two Dimensions of marble

This is what I calculated: Formula used: y(t) = y_0 + (v_0y)t + (1/2)(a_y)t^2 0 = 2.75 + 0 - (1/2)(9.8)t^2 t = 0.75s Then, I plugged time into the equation x(t) = x_0 + (v_0x)t 2 = 0 + (v_0x)(0.7) v_0x = 2.86m/s I don't think my answers are reasonable though. Plus, I'm not sure of how to find...
27. ### Motion in Two Dimensions of marble

I haven't learned that yet. I'm supposed use the kinematics equations for this problem.
28. ### Motion in Two Dimensions of marble

I'm thinking of finding the final velocity, or is that zero?
29. ### Motion in Two Dimensions of marble

A small marble rolls horizontally with speed v0 off the top of a platform 2.75 m tall and feels no appreciable air resistance. On the level ground 2.00 m from the base of the platform, there is a gaping hole in the ground. The hole is 1.50 m wide. For what range of marble speeds v0 will the...
30. ### Linear Motion of traffic

Thanks! That was a great explanation! I got 6957vehicles/h for part b.