Radius Definition and 1000 Threads

Homework Statement a person is doing pushups and its weight is 584 N, center of gravity is at waist and from waist to hands=.410m and from waist to feet=.840m. find the normal force on each hand and each foot Homework Equations The Attempt at a Solution do u have to find the...

OK I have no idea how to work this out. I've googled bending radius but it doesn't really help a great deal. It's the 2nd part of the last question: http://img535.imageshack.us/img535/4774/10579351.jpg There's nothing in my notes about it, but I guess it has something to do with how...

Homework Statement Find the radius of convergence of the following power series: ∑_(n=0)^∞[(2n+1)/2n] x^n) Homework Equations Ratio Test: lim_n->inf (a_n+1 / a_n) The Attempt at a Solution I got a big ugly fraction that involved both n and x

Homework Statement Assume that the density of positive charge in any Thomson atom is the same as for the hydrogen atom. find the radius R of a Thomson atom of atomic number Z in terms of the radius Rh of the hydrogen atom. Homework Equations The Attempt at a Solution I don't...

Homework Statement The radius of convergence of the sum (from n=1 to infinity) of n!x^n /n^n Homework Equations The Attempt at a Solution I ask way too many calculus questions on here.. This is everything I've done, written really badly.. Ratio test: (n+1)!xn+1/(n+1)n+1 times...

Homework Statement Find the radius of convergence for (sum from n=0 to infinity)7^(-n)x^(n). Homework Equations The Attempt at a Solution The problem above it was a similar sum, (7^n)(x^n). That answer was that the radius of convergence was 1/7. To do this one that I posted up...

Homework Statement A 2 kg car travels in a flat circle. At a certain instant the velocity of the car is 24 m/s West and the total acceleration of the car is 9 m/s 2 at 53 degrees North of West. What is its radius? Answer in units of km. Homework Equations F=ma w=(2pi)/T a= w^2...

An object with a mass M is rotating around an axis, with an arm of radius R at a certain speed V. Assuming that the movement is constant, and a 100% efficiency, how many watt of electrical power can this device generate ? For example purpose, we can take M=60 kg, R=5 meters and V=10 meters...

Homework Statement block 1 with mass of 680 g starts from rest at the top of a frictionless track at a height of H = 4.20 M above the ground. Block 1 collides with block 2 (m = 175 g) at ground level. The blocks stick together and barely complete one turn around a frictionless loop. find the...

Hi to all. Please help me to clarify this situation: There is a 4-wheel cart powered by friction drive using the dc motor. The cart will carry heavy stuffs on the top. what radius of wheels will be able to overcome a 1 cm high and 0.7 cm wide and 14 cm long speed bump(like a thin stick)...

The schwarszchild radius of an electron=1.353*10^-57m, and to work out the volume of a particle assuming it is spherical is 4/3*pi*radius^3 so the volume of an electron at its schwarzchild radius is 4/3*pi*1.353*10^-57^3 = 0??! WHAT DOES THIS MEAN :S

Homework Statement find the roc of: \sum_{n=0}^{\infty}\frac{(n!)^3}{(3n)!}z^{3n} Homework Equations limsup ratio test The Attempt at a Solution i think use of limsup is quite difficult as factorial there. but i do not know how to use the ratio test because z is another...

hi, how do you calculate the classical radius of nucleons or quarks? do you include only the electrostatic potential energy or also some nuclear potential energy?. i have read many times that the classical radius of nucleons is lower than the classical radius of the electron, is it right...

Homework Statement Beam of silver atoms are passing through air at a temp 273K and a pressure of 1 Pa. The beam is attenuated by a factor of 2.72 in a distance of 10^-2 m. Find the mean free path of the silver atoms and estimate the effective collision radius.. Homework Equations...

Homework Statement I'm trying to create a graph showing the relationship between radius and angular velocity for a toriod space station that maintains a constant angular acceleration of Earth's gravity (9.8 m/s^s) on it's rim. Homework Equations ac = r\omega^2 The Attempt at a Solution...

Homework Statement PHYSICS Gravity exercise!? What is the acceleration due to Earth's gravity at a distance from the center of the Earth equal to the What is the acceleration due to Earth's gravity at a distance from the center of the Earth equal to the orbital radius of the Moon? a =...

Homework Statement A curve of radius 151 m is banked at an angle of 11°. An 798-kg car negotiates the curve at 94 km/h without skidding. Neglect the effects of air drag and rolling friction. Find the following. (a) the normal force exerted by the pavement on the tires (b) the frictional...

Homework Statement while lying flat on a beach you see the sun set, and when the sun disappears you start a timer. Then you stand up, changing the position of your eyes(increasing height) by 1.7m. When the sun disappears from your view again you stop the timer which reads 11.1s. Calculate the...

I have a motor http://www.megabuy.com.au/gearbox-wi...utm_medium=cpc and i want to attach a spindle, like a circular thing directly onto the shaft. the circular thing has to have a radius, such that it lifts 0.5kg but does not lift 1kg, i do not know how to find the radius so it lifts...

I have a motor http://www.megabuy.com.au/gearbox-with-motor-12v-70rpm-p204324.html?utm_source=getprice&utm_medium=cpc and i want to attach a spindle, like a circular thing directly onto the shaft. the circular thing has to have a radius, such that it lifts 0.5kg but does not lift 1kg...

Homework Statement Determine the radius of Convergence using the ratio test of: \sum_o^{\infty}\frac{n^6}{3^n+n}(x+4)^{8n+1}\qquad(1) Homework Equations R = \frac{1}{\lim_{n\rightarrow\infty}\left|\frac{a_{n+1}}{a_n}\right|}\qquad(2)The Attempt at a Solution Ok. In order to use (2), we...

Geometry Problem Involving Circles and Fixed Radius- Please Help! I have a compass with radius X, and my friend has a compass with radius Y. We both draw a circle with our compasses so that our circles intersect at two points. Call these two points C and D. You draw a common tangent to both...

Homework Statement An alpha particle and beta particle, each with kinetic energy 35keV , are sent through a 1.1T magnetic field. The particles move perpendicular to the field. Homework Equations no idea. The Attempt at a Solution theres nothing on curvature radius in my...

Homework Statement A spherical asteroid has a density of 2600 kg/m^3. I throw a ball at the speed on 20 m/s. If the ball is to travel in a circular orbit, what is the largest radius of the asteroid possible to accomplish this? Homework Equations these are the equations I used.. escape...

Radius of proton due to QED?? In one account of the new findings of smaller proton radius, the claim was repeated several times that the radius of a proton was predicted by QED, in conflict with the new measurement. Why QED? I would think, within a proton, QCD is orders of magnitude more...

Homework Statement The string in the Figure is L = 102.0 cm long and the distance d to the fixed peg P is 73.4 cm. When the ball is released from rest in the position shown, it will swing along the dashed arc.How fast will it be going when it reaches the highest point in its swing? Homework...

Homework Statement I've got this problem on polar coordinates which says: A particle moves along a plane trajectory on such a way that its polar coordinates are the next given functions of time: r=0.833t^3+5t \theta=0.3t^2 Determine the module of the speed and acceleration vectors for this...

Homework Statement Suppose there is a Conical section (of a right circular cone) of total height 'l' and radii 'a' and 'b' (a>b). How do we derive the formula for the radius at a height 'h' (h<l) ?Homework Equations The Attempt at a Solution

Homework Statement a projectile of mass m is launched vertically from the surface of Planet Islander at a speed that is one-third the escape speed from the surface. If the projectile reaches a maximum height that is a distance h from the surface of the planet, what is the radius of planet...

Homework Statement A civil engineer is asked to design a curved section of roadway that meets the following conditions: With ice on the road, when the coefficient of static friction between the road and rubber is 0.1, a car at rest must not slide into the ditch and a car traveling less...

Homework Statement see attachment Homework Equations r=RoA1/3 Ro=1.2*10-15 The Attempt at a Solution 35 kiloelectron volts = 5.60761762 × 10-15 joules I could calculate the velocity if I knew mass but that wouldn't help with the radius? I think that I need to find A from the...

Homework Statement See figure attached for problem statement as well as my attempt. Homework Equations The Attempt at a Solution See 2nd figure attached. I don't know how to rid myself of that last n! I've got kicking around in the numerator. Any ideas?

Homework Statement If a plane is flying level at 950 km/h and the banking angle is not to exceed 40 degrees what is the minimum curvature radius for the turn?Homework Equations possibly F = ma = mv2 / r ? The Attempt at a Solution no idea where to start on this one, not sure where the angle...

Hi I need to calculate the radius of curvature of a reflector.I have a sound source (Ultrasonic transducer of 40 mm operating at 50 Khz) in air . I am trying to generate a standing wave using this sound source .As curved reflectors can help to amplify the sound pressure (I actually don't...

Homework Statement estimate the radius of the largest asteroid from which you could escape simply by jumping off. Homework Equations R^2= 3gh/4piGp The Attempt at a Solution Would I use this formula to solve it? Found it online but dose not seem right. this is a 2 part problem...

I understand how the formulas for classical electron radius are derived.. but what significance does the classical radius really carry? Obviously it's not really the size of the electron. So what does it mean?? Thank you for any help... Sorry, I'm new to this stuff.

Homework Statement Someone gave me this problem: finding the radius of the circle inscribed in the triangle with the given lengths. The Attempt at a Solution The person asking about this problem said it was taken from a beginning algebra textbook. I tried figuring it out using just...

Homework Statement A projectile is fired at spead v0 and angle \Theta. What is the radius of curvature of the parabolic motion a) at the top? b) At what angle should the projectile be fired so that the radius of curvature at the top equals half the maximum height? (the projectile is fired...

I am looking for data on the coefficient r_s, which is related to the radius of a sphere such that, for a given density of electrons, there is one electron pers sphere on average. I have seen it expressed as r_s = r/a_0 where r is the radius of the sphere and a_0 is the bohr radius. Does the...

Homework Statement A train enters a curved horizontal section of track at 100 km/hr and slows down with constant deceleration to 15 km/hr in 12 seconds. An accelerometer mounted inside the train measures a horizontal acceleration of 2 m/s^2 when the train is 6 seconds into the curve. Calculate...

I've been working on this for five hours and I am on the verge of despair! Can anybody help with this question? All I need is an equation! There are two extrasolar planets (X and Y) that are orbiting two stars with the same mass as our Sun (1.9891 × 10^30 kg), i.e. the planets are in two...

Homework Statement A particle moves along a circular path over a horizontal xy coordinate system, at constant speed. At time t1 = 3.70 s, it is at point (4.30 m, 5.50 m) with velocity (3.10 m/s)j and acceleration in the positive x direction. At time t2 = 13.0 s, it has velocity (–3.10 m/s)i...

Homework Statement Basically I don't understand how you do this - the course I'm doing keeps mentioning the orbital radius of extrasolar planets but doesn't tell you HOW to find it? Can anyone please help - in plain English, please, I'm not a natural scientist! Homework Equations...

Given the following parametric form of the Friedmann Equation for an open, dust-filled (matter-dominated) universe: a(x)={a_0 \Omega \over 2(1-\Omega)}(cosh(x)-1) t(x)={\Omega \over 2 H_0 (1- \Omega)^{3/2}}(sinh(x)-x) I am trying to calculate the Hubble Radius, R=c/H(t) where H(t)=(da/dt)/a...

Homework Statement If you paint a dot on the rim of a rolling wheel, the coordinates of the dot may be written as (x,y)=(R\theta+Rsin(\theta), R+Rcos(\theta) where \theta is measured clockwise from the top. Assume that the wheel is rolling at constant speed, which implies \theta = \omegat...

"Radius" of the Universe Hi, I have a very simple question about GRT. I use a picture which I personally like. Let us have a shpere (2D, embedded in 3D). Physics do only work on this sphere in this theoretical universe, so the forces work only along geodatics (there is no "above" or...

Homework Statement Two spheres are cut from a certain uniform rock. One has a radius 4.50cm. The mass of the other is 5 times greater. Find its radius Homework Equations r1 = 4.50cm r2 = ? when mass is 5x greater The Attempt at a Solution Looking at this problem I first thought...

Estimate the radius of a solar mass (2 × 1030 kg) black hole. How do I do it? I have literally no idea! Thanks in advance for any help.

Homework Statement A cyclotron is to accelerate protons to an energy of 5.4 MeV. The superconducting electromagnet of the cyclotron produces a magnetic field of 3.5 T, perpendicular to the proton’s orbits. a) When the protons have achieved a kinetic energy of 2.7 MeV, what is the radius of...

Homework Statement Suppose that, while lying on a beach near the equator watching the Sun set over a calm ocean, you start a stopwatch just as the top of the Sun disappears. You then stand,elevating your eyes by a height H=1.70 m, and stop the watch when the top of the Sun again disappears. If...