Homework problem Definition and 405 Threads

Ok let me just type the question and get to the real question I have. If you traveled one mile at a speed of 100 miles per hour and another mile at a speed of 1 mile per hour, your average speed would not be (100 mph+ 1 mph)/2 or 50.5 mph. What would be your average speed? (Hint:what is the...

Homework Statement The problem says: "A record rainstorm produced 304.8 mm (approximately 1 ft) of rain in 42 min. Estimate the average force that the rain exerted on the roof of a house that measures 10 m * 16 m. Indicate any assumptions you made. (Note: density of water is 1000 kg/m3"...

Homework Statement Homework Equations slit width = a , slit separation = b = d (at photo), tanQ=h/L m.λ=b.sinQ λ.b=sinQ B=π.d.sinQ/λ α=π.a.sinQ/λ Iq=Imx(cosB)^2 x (sinα/α)^2// The Attempt at a Solution My first move was to find intensity but I have no idea about the probability of...

Homework Statement Let C be the closed, piecewise smooth curve formed by traveling in straight lines between the points (-2,1), (-2,-3), (1,-1), (1,5) and back to (-2,1), in that order. Use Green's Theorem to evaluate the integral ∫(2xy)dx+(xy2)dy. Homework Equations Green's Theorem: ∫Pdx+Qdy...

Homework Statement There is a tether ball swinging around in a uniform circle on a rope that is 1.90m long. Marcus hit the ball so hard that the string holding the ball made a 20.0 degree angle to the horizontal. What is the tension in the rope if the ball has a mass of 1.40 kg? Assume that the...

Homework Statement ∞ n=3 ∑ ((-1)n (x+3)3n)/(2nlnn) Find radius of convergence, interval of convergence, values for x which series is: absolutely convergent, conditionally converge or divergence. Homework EquationsThe Attempt at a Solution I applied the Ratio Test and got |(x+3)3| lim...

Homework Statement A student holds a book at rest on the palm of her hand. She lifts the book straight up, bringing it to rest again at a higher point. 1. Is the net work done on the book positive, negative, or zero? 2. Is the change in the gravitational potential energy positive, negative...

Homework Statement Hello everyone, I am having immense trouble with this problem. I'm not too sure if this is classified as Advanced Physics, but currently I'm a high school senior in AP Physics. You are given a spring with spring constant k=40,000 N/M. A 2 KG block is put onto the spring...

I've got this problem with my HW. Would appreciate the help. Thanks. 1. Homework Statement A metal peace with the density of 10,4 g/cm3, has a hole on the inside. The metal weighs 8,2N in air and 7,1N in water. What is the volume of the hole? Homework Equations V = m / ρ m = Fg / g Maybe some...

Homework Statement Given the functions Q(v,w) and R(v,w) [/B] K = v(dQ/dv)r and L = v(dQ/dv)w Show that (1/v)K = (1/v)L + (dQ/dw)v (dW/dv)r I have the problem attached if for clarity of the information. Homework Equations I assume everything is given in the problem. The Attempt at...

Homework Statement (a)The current density across a cylindrical region of radius R varies according to the equation: J=J0(1-r/R), where r is the distance from the axis of the cylinder. The current density is the maximum J0 at the axis r=0 and decreases linearly to zero at the surface r=R...

Homework Statement I have attached the question in image format. Homework Equations The Attempt at a Solution I attached my attempt at solution as images. Kindly have look at them.

Homework Statement Lim ( 5+6x2)/(√(x3)) + 2x2 +1) x->∞ Homework Equations not allowed to use lhopitals rule The Attempt at a Solution first, i divided by x2, which yielded (5/(x2) + 6 + √(x)) / (2 + 1/x2 ) then i assumed that thelim x--> infi of 5/x2 = 0, lim x-->...

TLDR; I'm looking for a good online source for electromechanics material I can pre-learn prior to taking the course at university Hi folks, In the fall I'm starting my last semester of EE, and one of the courses we have to take is Electromechanics. We just found out who the professor is...

Homework Statement How divergence of r (cap)/ |r|^2 is equal to zero? Homework Equations r(cap)= x(cap)+y(cap)+z(cap) |r|^2 as x^2+y^2+z^2 The Attempt at a Solution I tried the problem and end up with with a different solution I took r(cap)= x(cap)+y(cap)+z(cap) |r|^2...

Consider two black holes: the left one has a mass M1= 5x10^30 kg, and the right one has a mass of M2= 9x10^30 kg, and they are a distance d= 3.0x10^6 m apart. A spaceship passing between them is having engine trouble and so the captain has to park the ship somewhere where he won't get sucked...

Why capacitance behaves as shortcircuited in uncharged state and why as open circuited when its fully charged..?? I am reallt doubtful..:confused: i=Cdv/dt...so if we r appyling a dc voltage ..in that case i should be zero.>! thn why short-circuited..??

Physics homework problem -- design a capacitor Homework Statement An engineer needs to design a capacitor with a capacitance of 1*10-6F using a material with a dielectric constant 260. If the dielectric strength of the material is 8*106 N/C, and the maximum voltage that the capacitor is...

Homework Statement I apologize for not utilizing built-in Latex, I'll have to work with that a little more.Question statement: Explain the paths, both transmitted and reflected, that a light ray of 400nm would take if it was incident perpendicular to the bottom face ofo the crystal. If the...

Homework Statement I need to figure out the trial function for the Laguerre equation, xy''+(1-x)y'+ny=0 Homework Equations The Attempt at a Solution I have found multiple examples of the Rayleigh Ritz method on google, however, I am completely dumbfounded as to where the trial functions are...

Homework Statement A rock is thrown vertically upward from the edge of a cliff. The rock reaches a maximum height of 18.6 m above the top of the cliff before falling to the base of the cliff, landing 6.60 s after it was thrown. How high is the cliff? Assume gravity= 9.8m/s2Homework Equations...

Hello, the problem statement reads thus: "Consider a low-speed flow of air over an airplane wing at standard sea level conditions; the free-stream velocity far ahead of the wind [point 1] is 100 mi/h [44.7m/s]. The flow accelerates over the wing reaching a maximum velocity of 150 mi/h [67.1...

Homework Statement A 165g plastic block is set up against a spring. The block rests on a smooth (I'm assuming this implies that there is no friction involved) horizontal surface. The block is pushed into the spring, compressing it a distance of 15.0 cm and released. The spring constant is k=...

Homework Statement Hi, I have a really short (and dumb) question. In one of my homework problems they talk about a vector w, such that w=e1+e2+e3. (In R3.) The Attempt at a Solution I guess they mean that: e1=(1,0,0), e2=(0,1,0) and e3=(0,0,1). So w=(1,1,1). Right?

Homework Statement I am having problems with the following problem: "For a noninteracting gas of N particles in a cubic box of volume V = L^3 where L is the length of the side of the box, find the solution, \rho (\mathbf{p}^{3N},\mathbf{q}^{3N},t) , of the Liouville equation at time t, where...

Homework Statement Doug pushes a 5.30 kg crate up a 2.20-m-high 20 degrees frictionless slope by pushing it with a constant horizontal force of 27.0 N. What is the speed of the crate as it reaches the top of the slope? a) Solve this problem using work and energy. Homework Equations...

Homework Statement I am having a hard time understanding the length measurement in the problem. We went over this example in class and the length, L, was something I didn't realize until now. Question: A 6-ft-long steam pipe is made of A-36 steel with σ=40 ksi (yield stress). It is...

Homework Statement Let a be a real number such that 1 < a < 2 ,{an} is a sequence defined by a1=a, an+1=|an|-1 (n=1,2,3...) And put sn=a1+a2+a3+...an i)Find the a4,a5,a6,a7 i)Find a4,a5,a6,a7 The Attempt at a Solution I don't even know how to start.Maybe someone could give me an idea.

Homework Statement Sketch the region R bounded by the curves y = x, x = 2 - y^2 and y = 0. This is the initial part of an integral problem and I'm just curious about the method here. Homework Equations The Attempt at a Solution So, would it be proper to take the x = 2 - y^2...

Homework Statement I have just planted a new tree. To support the tree in bad weather, I attach guy wires from the trunk of the tree to stakes in the ground. I cut 32 feet of wire into four equal lengths to make the guy wires. I attach four guy wires, evenly spaced around the tree. I put...

Homework Statement How many grams of NaCl must you add to 750g of water to make a 0.35 molal solution? Ans. 7.59g Homework Equations molality=\frac{mol_{solute}}{kg_{solvent}} MW of NaCl = 23 + 35.45 = 58.45 g/mole The Attempt at a Solution...

I'm trying to put together a little physics project, and I've constructed a rudimentary stringed instrument using a 2-liter bottle and some string. The string is fed through the bottom of the bottle and wound around a small dowel at the top end, and a small hole has been cut near middle of the...

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.

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 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 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

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...

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...

Homework Statement The problem wants me to give an example of two sets that satisfy this condition A∩P(A)ε B Homework Equations None The Attempt at a Solution For my example I used this example A={1,2}...

Homework Statement Ts (subscript s) = 2∏*√(4.5*10^-2 kg / 2.0*10^3 kg/s^2) kg = Kilograms s = seconds Ts = ? Homework Equations I do not have any relevant questions. The Attempt at a Solution Ts = 2∏*√(4.5*10^-2 kg)/√(2.0*10^3 kg/s^2) Simplified Ts = 6.28*[(0.212 kg)/√(44.72...

Homework Statement Find the Eigenspace of the following matrix: \begin{bmatrix} 1 & 3 \\ 4 & -3 \end {bmatrix} I'm skipping a few steps but the Eigenvalues are -5 and 3. Let's starts with -5. Skip a few more steps, I know I'm right, just trust me. We now have the following matrix...

Homework Statement referring to the attatchment. the current consists of two semi circles. the question asks me to find the voltage across a 47-uF capacitor when t = 2ms. Homework Equations v(t) = 1/C ∫ i(t)dt +v(t0) {I realize their has to be limits for the integrand,I just can't type...

Homework Statement show that for positive r and s, with r<s, we always have: r<(r+s)/2<s and 2/[(1/r)+(1/s)]^2< 2rs< (r+s)^2 Homework Equations The Attempt at a Solution i have shown that r<s because r+r<s+r, 2r<s+r, r<(s+r)/2 and 2r< (2s+2r)/4 (r+s)^2= r^2+2rs+s^2...

Homework Statement A roller-coaster car has a mass of 1150 kg when fully loaded with passengers. As the car passes over the top of a circular hill of radius 16 m, its speed is not changing. (a) At the top of the hill, what is the normal force (using the negative sign for the downward...

Homework Statement let a=360.9±0.1, let b=180.4±0.1, let c=212.5±0.13 and let d=211.7±0.16 whats f (including uncertainty) where f-1 = ((a/b)-1)/((c/d)-1) Homework Equations add the percentage uncertainties in quadrature if dividing two variables add the absolute uncertainties...

Homework Statement Solve for n in the following equations: n-2\mid n^{2}-n+3 Homework Equations The Attempt at a Solution Should i use the euclidean division to solve it? Thank you before hand. Edit: When i used euclidean division i got n+1 and a remainder of 5 but i don't know how to get n.

Homework Statement (i) What is the strength and direction of the force per unit length acting on a straight conductor carrying an electrical current, I, in a magnetic field, B? (ii) The figure below shows a square frame of aluminium set at an angle θ to the direction of a strong static...

Homework Statement Bobo, Coco, and 8 other students are arranged to sit in 2 rows of 5 students. If these 10 students take their seat randomly, find the probability that Bobo and Coco are sitting in the same row but not next to each other. The Attempt at a Solution Bobo and Coco...

Homework Statement When light is shined on thin films the interference pattern results in: a. there is no interference pattern *b. rainbow like colors c. light and dark pattern with no separation of colors d. a mirror quality reflection e. polarization of the light The...