Circular Definition and 999 Threads

Homework Statement Homework Equations F=ma ac=v^2/r f=uN v=v0+at w=v/r The Attempt at a Solution v=v0+at v=vo+umv^2/r v^2(u/r)-v+vo=0 I don't see what differential equation i could use since the speed is dependent on the friction (equal to friction coeff times centripetal force) which in...

Homework Statement http://www.webassign.net/hrw/W0490-N.jpg The figure above shows three circular arcs centered on the origin of a coordinate system. On each arc, the uniformly distributed charge is given in terms of Q= 2*10-6C. The radii are given in terms of R = 10cm. What is the magnitude...

Homework Statement A 0.020-kg mass is attached to a 1.2-m string and moves in a horizontal circle with a constant speed. The tension in the string is measured at 0.200 N. What is the measure of angle θ? Homework Equations ∑F=ma, a=v^2/r The Attempt at a Solution I broke down the forces at...

1. In the attached imjage, the centre of gravity of an open door acts at G equal to 255N; a) Determine the x,y,z, components of reaction at the hinge A in equilibrium b) Determine the force along CB Little stuck with this problem, obviously this falls under resolving forces. I assumed Az,Ay = 0...

Homework Statement NASA’s Vomit Comet simulates zero gravity by flying parabolic arcs of radius r and speed v to stimulate free fall. If the pilot flies a parabolic path which has a radius of 1km, calculate the speed (*in km/hr) the plane must travel at in order to stimulate free fall...

Homework Statement A car traveling on a flat (unbanked), circular track accelerates uniformly from rest with a tangential acceleration of 1.70 m/s2. The car makes it one-quarter of the way around the circle before it skids off the track. From these data, determine the coefficient of static...

Passing light through a circular sieve: Well, actually, let’s think about radar or microwaves with a wavelength of order a centimeter or two, so you can tailor your aperture, say by etching a silver screen on glass. If you have a reflective metal screen, and you cut a long narrow rectangle in...

Homework Statement How to calculate the magnetic field at the centre of a circular current (I) loop of radius r using Ampere law Homework Equations B = μ0I/2r The Attempt at a Solution I take circulation along the circular closed path of radius r passing through the center of the loop and...

Hi, I'm trying to write the current density for such circular loop in spherical coordinates. For a circular loop of radius a that lies in the XY plane at the origin, the current density it's simply: \mathbf{J}= \frac{I}{2\pi\sin\theta}\delta(\theta-\frac{\pi}{2})\frac{\delta(r-a)}{a}\hat{\phi}...

Homework Statement i was going through uniform circular but a confusion popped out of my head . as i have read before the Rutherford atomic model was only rejected due to the fact that electrons moving in circular orbits need to accelerate constantly to maintain a uniform speed but the...

Homework Statement Kim has her coffee cup on her car's dash when she takes a corner with radius 4 m and 20 km/h. What is the minimum coefficient of static friction which would allow the coffee cup to stay there without slipping? Homework Equations Can someone show me the steps in how they...

Homework Statement Small mass ##m## ball has a negative charge ##q## and is hanging on an inelastic string which has a length of ##l##. What is the smallest velocity that one need to impart on this ball for it to make one revolution? There is also a uniform magnetic field ##B## as shown in the...

Homework Statement Two circular lines of charge are centred at the origin and lie on the xy plane. The inner loop has a radius of a and a total positive charge q. The outer loop has a radius of b and total negative charge -q. (a) Use Coulomb's Law to calculate the electric field on the z-axis...

Homework Statement A 15 kg satellite has a circular orbit with a period of 4.4 h and a radius of 3.5 × 106 m around a planet of unknown mass. If the magnitude of the gravitational acceleration on the surface of the planet is 1.2 m/s2, what is the radius of the planet? Homework EquationsThe...

Dear All: I have recently encountered a small question regarding the determination of the degree of circular polarization of light. In an optical experiment, we are trying to create a circular polarized light beam by passing a HeNe-laser through a linear polarizer and a quarter wave plate (in...

Homework Statement Find the magnetic field at position z (z=0 in the plane of the ring) along the rotation axis for a circular ring of radius r, carrying a uniform linear charge density λ, and rotating about its axis with angular velocity ω. Homework Equations I=q/t ω=2πf f=1/period...

I recently took an exam in my engineering mechanics class and passed the exam except for one question. I have been trying to solve this question after the fact and determine the solution, however neither I nor several engineering tutors have had any success. The professor refuses to give...

Homework Statement Thewheel is rotated in the anticlockwise direction...The correct reaction force is drawn using the blue pen . I don't understand why the reaction force isn't directed to the left ? which is drawn using the red colour ? IMO, the red colour should be correct because the...

Why is there no component of tangential acceleration in uniform circular motion? I think its because when we apply the WE Theorem (Work-Energy Theorem) as follows: Work Done = ΔKE => F.S = 1/2*m*(vf2 - vi2), =>(ma).s = 1/2*m*(vf2 - vi2) => (ma).s = 1/2*m*(0) (since the speed remains constant in...

Homework Statement Homework Equations Circular Motion Equation The Attempt at a Solution I solved the problem and got the result to be 6 m/s2 but it is not one of the answers. I was pretty sure of my solution. So, are all choices wrong? F = ma mg sin 37 = ma a = g sin 37 = 6.01 m/s2

Homework Statement A police officer in hot pursuit drives her car through a circular turn of radius 356 m with a constant speed of 70.9 km/h. Her mass is 57.1 kg.What are (a) the magnitude and (b) the angle (relative to vertical) of the net force of the officer on the car seat? (Hint: Consider...

Homework Statement A particle moves along a circular path over a horizontal xy coordinate system, at constant speed. At time t1 = 3.30 s, it is at point (5.10 m, 6.80 m) with velocity (3.90 m/s)## \hat j ## and acceleration in the positive x direction. At time t2 = 9.90 s, it has velocity...

Homework Statement There is a counterclockwise current I in a circular loop of wire situated in an external magnetic field directed out of the page as shown. The effect of the forces that act on this current is to make the loop Select one: a. expand in size X b. contract in size c...

Homework Statement A particle moves along a circular path over a horizontal xy coordinate system, at constant speed. At time t1 = 3.30 s, it is at point (5.10 m, 6.80 m) with velocity (3.90 m/s) ## \hat j ##and acceleration in the positive x direction. At time t2 = 9.90 s, it has velocity...

Homework Statement A 0.020-kg mass is attached to a 1.2-m string and moves in a horizontal circle with a constant speed of 1.50 m/s, as shown in the figure. What is the measure of angle θ? What is given: m = 0.020kg v = 1.50 m/s L = 1.2 m Homework Equations Lengths L = 1.2m Lsinθ = r...

I'm moving on to a new area of focus at work and have found myself analysing a vibration issue. I've had the basics a BSME gets you at an accredited university (20 yrs ago), but am rusty to say the least. I'm looking for guidance on good reading materials to knock the rust off. My problem is...

Homework Statement A helium-neon laser ( ##\lambda =633nm##), is built with a glass tube of inside diameter 1.0mm. One mirror is partially transmitting to allow laser light out. From an optical perspective, the laser beam is a light wave that diffracts through a 1.0mm diameter circular...

Homework Statement Homework Equations I have some equations relating B to I but I don't really know if they are useful The Attempt at a Solution I actually don't even know where to begin on this, my notes are confusing and vague :(

Homework Statement A particle moving along a straight line can have nonzero acceleration even when its speed is zero (for instance, a ball in free fall at the top of its path). Can a particle moving in a circle have nonzero centripetal acceleration when its speed is zero? If so, give an...

Homework Statement A solid sphere of mass M and radius a is released at vertical height y=R and rolls down a circular bowl without slipping, find an expression for the velocity of the sphere's center of mass at the bottom of the bowl. 2. Homework Equations ##I=I_c+Md^2## I=\frac {2} {5}...

Homework Statement An object is moving uniformly in circles with a radius of 5m and a frequency of 2 Hz. What is its instantaneous velocity? Homework Equations [/B]The Attempt at a Solution The problem i am dealing with is the frecuency. I am not here for an answer or to cheat. I am...

Hi guys... So i searched the net for 2 whole days and found a couple of topics on how static friction is responsible for creating the force required to keep the body moving in a circle.. Friction points towards the center of the circle ONLY when the car is free wheeling i.e moving at a constant...

Homework Statement This isn't a homework problem, but I was just thinking of the following question: Suppose that a merry go round spins with a constant speed (so its radially accelerating towards the center), and a man want to jump onto the merry go-round while its spinning. In what way...

Homework Statement The Moon’s nearly circular orbit about the Earth has a radius of about 385 000 km and a period T of 27.3 days. Determine the speed of the Moon. Determine the magnitude and direction of the Moon’s acceleration. Mark Criteria: A)determining the correct period of motion in...

Homework Statement The temperature distribution of a circ plate with radius ##a##, ##f(r,\theta,t)##, follows the diffusion equation ##\nabla^2f=\frac{1}{\alpha^2}\frac{\partial f}{\partial t}##, with a temperature of zero along the border. The initial temperature is...

1. The problem The answer is A. Homework Equations x = Acoswt y = Asinwt The Attempt at a Solution C is not correct because the x & y positions are in terms of sin & cos, so the acceleration can't be constant. D is not correct because x & y are oscillating in value. E is not correct because...

So i have a thin circular ring laying at the XoY plane, inner radius of the ring is a, outer is b, density of electricity is given by expression ρ=ρ0*b/r , where ρ0 is a constant and r ∈ (a,b). I have to find a potential of the point P with coordinates (0,0,z).I tried to do it two ways, but...

Homework Statement An aeroplane loops the loop in a vertical circle of radius 200 m, with a speed of 40 m s^-1 at the top of the loop. The pilot has a mass of 80 kg. What is the tention in the strap holding him into his seat when he is at the top of the loop? Answer: 160 N. Homework...

Homework Statement A ball of mass m is attached to a rigid vertical rod by means of two massless strings each a length L. Both strings are attached on the rod a vertical distance D apart. The rod, strings, and ball are rotated at some speed and both strings are taught. If the tension in the...

Homework Statement Prove that for any three vectors ##\hat a, \hat b ## and ## \hat c##, ##\hat a \cdot (\hat b \times \hat c)## = ##(\hat a \times \hat b) \cdot \hat c ## Homework Equations [/B] ## \hat i \cdot \hat i = \hat j \cdot \hat j = \hat k \cdot \hat k = (1)(1)\cos(0) = 1 ## ##...

Hi friends..I'm struggling with an interesting puzzle...Suppose there is a circular conducting loop of radius 1/π cm, one half of which is made of a material with resistance 1Ω and the other half from a material with resistance 5Ω. If somehow, one managed to set up a changing magnetic field...

Such as the figure Why the string could not be horizontal when the rubber bungis moving in a horizontal circle? Only moving at conical pendulum? By the way, if tension is equal to weight(W), have any conclusion?

Homework Statement How is ##\frac{v}{v_M} = \frac{\sqrt{A^2 - x^2 }}{A}## derived? Homework Equations n/a The Attempt at a Solution I don't see a right angle in the picture anywhere, so I don't see how pythagorean's theorem is valid.

Homework Statement Sorry to bother you guys, I've heard that Ampere's Law is either ineffective for calculating the B field due to a circular loop or needs some modification (I wasn't sure which). I'm trying to figure out why this doesn't work so I can get a better understanding of Ampere's...

Hi everyone! Just joined the fórum after a lot of hours searching the web and Reading some books...I have one question, didn't found na answer to it...but let's give it a try ;) How can you determine the optimal circular pitch and in consequence the optimal diametral pitch of a gear (increasing...

I am trying to understand circular polarization and Real 3D glasses.I am sure that answers will lead to other questions. Question 1. Are Real 3D glasses merely quarter wave plates with each eye set at 90 deg angles to the other? or.. Question 2. Do Real 3D glasses consist of a linear...

Homework Statement Consider a satellite in circular low Mars orbit 300km above the planetary surface. R = 3396km M = 6.419 x 1023kg G = 6.674 x 10-11m3/kg/s2 Find the orbital velocity of the satellite (using the given values, I assume, as there is some inaccuracy in the real-life mass value...

Hey guys first time poster. I have written a 2D ray tracer in Mathematica. It's very basic, all it does is use Snell's law to trace ray refraction and very basic absorption. The set up is a central absorbing circle surrounded by circular lenses. The central circle is a perfect absorber, so if a...

Homework Statement (See image) a closed circular wire A lies in the plane of the wire B in the circuit. Deduce the direction. Of the induced current in A when (A) the switch is closed (B) the switch is opened (C) the wire A is raised out of the plane of the paper. Homework EquationsThe...

Homework Statement \[/B] Joey spins a laptop then he releases it, at an angle. Assuming no wind resistance, the laptop (has a rubberized case) hits the concrete and drags across the concrete for 5.3 seconds. What is the coefficient of friction between the rubber and concrete and what distance...