Homework Definition and 998 Threads

Homework Statement An electron is accelerated from rest to a velocity of 2.0x10^7 m/s. a) if the electron traveled 0.10m while it was being accelerated, what was its acceleration? b)How long did the electron take to attain its final velocity? V1= 0m/s V2= 2.0x10^7m/s d= 0.10m a=...

Homework Statement Currently studying for a physics final on Wednesday 12/12/12 The problem can be found hereHomework Equations Not very sure. vfball=(v0(mball-mplank)+2mplankv0,plank)/(mball+mplank) mballv0=(mball+mplank)vf The Attempt at a Solution I have no idea how to do a. I've tried...

hey everybody :) i am new here and i need ur help. I have to solve this problem for home work tomorrow.Topic is forces in the body. I attached it. I actually need help for the whole first question. thx u in advance. Please try to explain it not too difficulty. thanks u :) Homework...

Homework Statement A sign is suspended from two strings as shown. Determine the wheight of the sign. Left string: Fτ=25 Newtons; ∅=40 degrees Right String:Fτ=25 Newtons; ∅=40 degrees Homework Equations i no that the mass is at equilibrium, so the tension forces are equal and opposite...

Homework Statement A steel plate has the form of one-fourth of a circle with a radius of 60 centimeters. Two two-centimeter holes are to be drilled in the plate positioned as shown in the figure. Find the coordinates of the center of each hole.Homework Equations I know it's got to be a simple...

Homework Statement If the period of a 70.8-cm-long simple pendulum is 1.91 s, what is the value of g at the location of the pendulum? Homework Equations I don't know of any that relate the period, radius and the value of g The Attempt at a Solution The thing is, I'm completely...

A moon is orbiting around the planet with a constant distance of 4.0 x 10^8 with... Homework Statement Question/w formulas are in attachment. I know I've been given two masses, 5.5 and 7.35 x 10^ 22 kg, and a distance of 4.0 x 10^8. But what I don't understand is the speed of 950 m/s and...

Homework Statement ∫x3e5x2 dx Homework Equations uv-∫vdv The Attempt at a Solution I've tried this one a few times, but keep getting answers that are just out there. Could someone, if possible, work out just the beginning.

Homework Statement A painter (mass 61 kg) is walking along a trestle, consisting of a uniform plank (mass 20.0 kg, length 6.00 m) balanced on two sawhorses. Each sawhorse is placed 1.40 m from an end of the plank. A paint bucket (mass 4.0 kg, diameter 28 cm) is placed as close as possible to...

The main water enters a house on the first floor. the line has a gauge pressure of 1.9x10^5Pa a) A faucet on the second floor 6.50 meters above the first floor is turned off. what is the gauge pressure of this faucet? b)how high could a faucet be before no water would flow from it even if the...

Homework Statement We've shown if G_{1},G_{2},...,G_{n} are subgroups of G s.t. 1)G_{1},G_{2},...,G_{n} are all normal 2)Every element of G can be written as g_{1}g_{2}...g_{n} with g_{i}\inG 3)For 1\leqi\leqn, G_{i}\capG_{1},G_{2},...,G_{i-1}=e then G\congG_{1}xG_{2}x...xG_{n}...

Homework Statement --F-->{3.9kg}{5.8kg}{8.3kg} Three blocks are in contact with each other on a frictionless horizontal surface. A 413 N horizontal force is applied to the block with mass of 3.9 kg as shown in the figure below. The acceleration of gravity is 9.8 m/s2 . d)What...

Homework Statement The question c) I have attached. Capture th.PNG (27.7 KB) Capture th2.PNG (14.8 KB) Homework Equations The Attempt at a Solution Use U=f(T,V) and H=f(T,P), then get Cp and Cv, so I can get gamma. then k=(1/v)(dv/dt) but I still can't prove it.

Here is my homework question. I am stuck on one part of it, and it is ok for me to receive guidance, not answers without effort. Question: Let R be the region bounded by the following curves. Use the shell method to find the volume of the solid generated when R is revolved about the x-axis...

Homework Statement I have been trying this question since 5 hours but I am lost ! Any help would be appreciated Some moron kids are trying to tip over a storage bin as shown. The bin weighs 7100 N, w = 2.2 m, h = 3 m, d = 1.6 m, and theta = 20 degrees. With what force do they need to push in...

Homework Statement an airplane, whose air speed is 580km/h, is supposed to fly in a straight path 38N of E. But a steady 72km/h wind is blowing from the north. In what direction should the plane head? i know the answer is 43.6 N of E but i am not completely sure how to get it Homework...

Homework Statement Suppose that the function f : R → R is differentiable. Define the function H: R → R by H(x) = ∫−x to x of [ f (t) + f (−t)]dt for all x in R. Find H'' (x). Homework Equations The Attempt at a Solution i divided it up into ∫ 0 to x of [ f (t) + f (−t)]dt and -∫...

I was able to solve all my other problems for homework but I'm having problems with this one. Any help would be appreciated. Thanks A 1200 kg frictionless roller coaster starts from rest at a height of 19 m. What is its kinetic energy when it goes over a hill that is 11 m high?

Homework Statement James Bond and Dr. No are engaged in fisticuffs on a board overhanging a pool. Dr. No now pulls out his weapon. oh no!. Bond is in trouble again. Bond quickly calculates the torques and leaps off the left end of the board leaving Dr. No on the right. Is Bond safe? That is...

Homework Statement In the following diagram (see attachment), w=80N and the net force is 0. The Attempt at a Solution I basically made two free body diagrams and applied Net Force = 0 for each axis, obtaining 4 equations with 4 variables (T1,T2,T3,T4). I got T1=56N T2=98N T3=115N...

I'm taking mechanics and my professor said that the upcoming test will be very similar to the homework problems assigned. But he said we should know how to work the problems backwards. So in the homework he gives us a and b and we have to solve for c and he's saying that on the test he will...

Homework Statement I actually have posted this question in another part of this forum, but due to lack of responses, I felt maybe I posted it in the wrong section. Can you all take a looksie please? https://www.physicsforums.com/showthread.php?t=645676

I have no clue where to begin with these assignments, can anyone walk through the steps to these? 1. An automobile accelerates from rest at 1.7 m/s2 for 22 s. The speed is then held constant for 29 s, after which there is an ac- celeration of −5.8 m/s2 until the automobile stops. What...

Homework Statement ions and electrons produced in the electric field between the hand and the plate (3.0 x 10^6 Vm^-1) are accelerated and may collide with other particles, causing further ionisation. Calculate the force on an electron in this field. Homework Equations E=V/d The Attempt at...

Hi, I have a question. Suppose you have two concentric cylinders of radii a and b with opposite uniform surface charges, line charges or something to that effect. Now, I know (or was told) that the E-field between the two, that is for a<r<b, is equal to the field from the inner cylinder (radius...

Homework Statement Number 3 in the attached file Homework Equations Not sure The Attempt at a Solution Been staring at it for about an hour now and still don't have a clue. Can someone point me in the right direction? Thanks.

Homework Statement Someone throws an object upwards at 5 m/s from a window twelve feet high. A) what is the velocity of the pen at 1 second after it was thrown? Homework Equations D = vi * t + (at^2)/2 Vf^2 = vi^2 + 2adThe Attempt at a Solution I keep getting 4.8, but the answer is 1.2m/s...

Homework Statement Find three positive numbers whose sum is 12 and the sum of whose squares is as small as possible. Homework Equations The Attempt at a Solution I don;t even know how to start this one, this is a section from partial derivatives on the max and mins. Please i need guidance...

Prove that ordda | ordma, when d|m. Some conditions are 1 ≤ d, 1 ≤ m, and gcd(a,d)=1. What I have so far: let x=ordma, which gives us ax\equiv 1 (mod m) \Rightarrow ax=mk+1 for some k\inZ Let m=m'd. Then ax=mk+1=d(m'k)+1

Homework Statement Homework Equations radius of gyration: r = root (I/m) I = moment of inertia m = mass parallel axis theorem given above The Attempt at a Solution Okay, so I think the moment about CM is just m*0.24^2, but after that, I'm less sure. Is the moment about the hip just...

The question is: Henry is bouncing on a trampoline, using the given data below, calculate the height at which Henry will bounce to from his lowest position. Lowest position: -0.50m Henry's Mass: 75kg upward acceleration: 13.3 m/s^2 upward force: 1750N downward force: 750N Net force...

Homework Statement I made a quick drawing of the circuit, and I apologize because I am not good at using the computer to draw circuits! Anyway, in this particular circuit R=200Ω , and L=5mH. For part a I am supposed to find the Transfer Function H(jw) = (Vout/Vin) in terms of ω. For part b...

Homework Statement Formation of the Solar System The distance of Venus is about 0.7 AU, and the orbital radius of Jupiter is about 5.2 AUs. How many times hotter is the region where Venus formed compared to the region where Jupiter formed? Enter numbers and decimal point only. Round off...

Homework Statement A car goes over a speedbump, which has the cross-section of a cylinder of radius R embedded in the roadway. If you want a car driving with a speed Vo to be impeded, how large must R be? I'm very confused about this problem because we have not discussed the topic in class...

"At what minimal height must be situated the point of reflection of a radio wave emitted in Montreal and received in Paris? The distance which separates both cities is 5 400 km and the radius of the Earth is 6 400 km." I don't even know where to start, we didn't learn this. I would assume the...

Homework Statement A subway train starting from rest leaves a station with a constant acceleration. At the end of 6.27 s, it is moving at 10.4082 m/s. What is the train’s displacement in the first 4.59591 s of motion? Answer in units of m

Homework Statement A 2,254-kg car is moving down a road with a slope of 10 degrees while speeding up at a rate of 1.1 m/s^2. What is the direction and magnitude of the frictional force? (define positive in the forward direction, i.e., down the slope)? Homework Equations ax=μgcos-gsin...

1. A uniform metal tube of length 5.0 m and mass 9.0 kg is suspended horizontally by two vertical wires attached at 50 cm and 150 cm respectively from the ends of the tube. Find the tension in each wire. Okay, so I've sketched a diagram out and labelled it. The support would be somewhere...

Linear Algebra Homework help! Homework Statement Suppose a particular object is modeled as moving in an elliptical orbit centered at the origin. Its nominal trajectory is described in rectangular coordinates (r;s) by the constraint equation x1r^2 +x2s^2 +x3rs = 1, where x1; x2; and x3 are...

I am trying to do laplace transform of y(t)=e^{-at}\cos (bt)\;. The answer should be: \frac {s+a}{(s+a)^2+b^2} But here is my work, I can't get rid of the -ve sign. I must be too blind to see the obvious, please help: \overline{y(s)}=\int^∞_0 e^{-(s+a)t}\cos (bt) dt\;=\; \frac 1 b...

Homework Statement A 5-kg object initially slides with speed V0 in a hollow frictionless pipe. The end of the pipe contains two springs, one nested inside the other, as shown above. The object makes contact with the inner spring at point A, moves 0.1 meter to make contact with the outer spring...

Homework Statement A student proposes to study the gravitational force by suspending 2 100 kg sperical objects at the lower ends of cables from the ceiling of a tall cathedral and measuring the deflection of the cables from the vertical. The 45 m long cables are attatched to the ceiling 1m...

Homework Statement So basically this is a two part question, first part was find acceleration of the system (which i already found) with a coefficient of friction of 0.1. B) asks you what coefficient you need for the object not to move? Homework Equations The Attempt at a...

Homework Statement \frac{3x + 1}{2x - 6} < 3 Homework Equations The Attempt at a Solution \frac{3x + 1}{2(x -3} < 3 \frac{3x +1}{x - 3} < 6 Assume x < 3 3x + 1 > 6(x - 3) 3x + 1 > 6x - 18 3x + 1 - 6x + 18 > 0 19 > 3x x < 19/3 No Contradiction. Assume x > 3...

The guidelines below will help you avoid some common obstacles to getting help. Executive Summary 1. Choose an appropriate thread title 2. Use the homework template 3. Reproduce the problem statement accurately 4. Show us that you've thought about the problem 5. Do not simply post images of the...

Homework Statement Is there an equation which I can use to calculate this? Homework Equations The Attempt at a Solution I think the SI units for pressure are kgm^-1s^-2 but that's all I know. I have tried to put numbers into that to get an answer but I can't get it to work. Thanks.

Homework Statement Homework Equations All should be there, except taylor series, which is found here: http://mathworld.wolfram.com/TaylorSeries.html The Attempt at a Solution For part a, I got: F(r)= \alpha(ke2)((-r0/r2)+(r0n/rn+1)) since force is the negative...

True Story "Can you do my homework" Many years ago when I was studying at University I shared lodgings with several other students. The landlords teenage son was always pestering us to help with his physics homework. One day he had a problem that required a long descriptive answer. To get rid...

Homework Statement two charged particles held fixed in the xy plane are: q1= +3.0 μC, x1=3.5 cm, y1= 0.50 cm, and q2= -4.0 μC, x2= -2.0 cm, y2= 1.5 cm. (question 1) What is the magnitude and the direction of the electrostatic force on q2. ? (question 2) Where would a third charge q3= +4...

Homework Statement The first problem I am having trouble with is as follows: A child pushes a 40kg sled across the ice at a constant speed. If μk = 0.05 calculate the force applied to the sled. Homework Equations I know that f=\muFN The Attempt at a Solution I know that the...