Maximum Definition and 1000 Threads

Homework Statement Calculate the maximum bending moment on the bridge section using the values given. (REFER TO DIAGRAM ATTACHED) mass of bridge = 9250 kg mass of car = 2250 kg length of bridge section = 26 m Homework Equations I worked out previously that: Reaction at A = reaction at B =...

Lets say you have a block of iron with a mass "m" exposed to an infinitely strong magnetic field "B." If there was a strong wooden interface preventing this iron block from moving towards the magnetic field source, how can you calculate the force the iron block would exert on the wooden board?

Hi, I am trying to build a conductivity meter as part of a school project (I have to measure the conductivity, among other things, of local water systems). Unfortunately, I cannot buy one for this project, as it should be home-made for these purposes. If I wanted to create a meter that...

Homework Statement Find the largest possible value of \sqrt{(x-20)(y-x)}+\sqrt{(140-y)(20-x)}+\sqrt{(x-y)(y-140)} subject to ##-40≤x≤100## and ##-20≤y≤200##. Homework Equations The Attempt at a Solution Factoring out ##\sqrt{(x-20)(y-x)(140-y)}## the given expression can be...

ladies and gents I have been set a question for homework which is one where if you get one part wrong then the rest of your answers are in correct. It is a 3 questions in one question and i have answered 1 and 2 but can't seem to do part 3 the question is A torque T = 75Nm is applied to...

[b]1. A 2.5GWth nuclear power plant operates at a high temperature of 570°K. In the winter the average low temperature at which it dumps waste heat is 268°K; in the summer it’s 295°K. Determine the thermodynamic efficiency of the plant in each season, and then derive from it the maximum possible...

Fluctuation theorem says that there will be fluctuations in microscopic scale that results local decreases in entropy even in isolated systems. According to the Poincaré recurrence theorem, after sufficiently long time, any finite system can turn into a state which is very close to its initial...

Hello! How do I calculate the maximum possible rotational speed of a thin walled hollow cylinder? In other words, at what rotational speed will it explode due to centripetal force? This picture shows the plane of rotation...

Homework Statement A circuit is constructed with a resistor, two inductors, one capacitor, one battery and a switch as shown. The value of the resistance is R1 = 481 Ω. The values for the inductances are: L1 = 281 mH and L2 = 163 mH. The capacitance is C = 85 μF and the battery voltage is V...

Homework Statement Here is the question along with the solution: Can anyone explain why the terms I circled in red are different? For the first term there is a negative sign but then the second term does not? Why did it disappear?

Let $E\subset\mathbb{R}^n$ and $f: E\rightarrow\mathbb{R}$ be a continuous function. Prove that if $a$ is a local maximum point for $f$, then either $f$ is differentiable at $x = a$ and $Df(a) = 0$ or $f$ is not differentiable at $x = a$. Deduce that if $f$ is differentiable on $E^o$, then a...

Homework Statement I have found the question I am having trouble with here: http://www.chegg.com/homework-help/questions-and-answers/block-mass-m-rest-surface-incline-adistance-h-10cm-base-height-incline-ish-50cm--coefficie-q218123 Homework Equations See below The Attempt at a Solution After...

Homework Statement A car travels around a circular curve on a flat, horizontal road at a radius of 42meters. the maximum frictional force between the tyres and the road is equal to 20% of the weight of the car calculate the maximum speed at which the car can travel around the curve at a...

Homework Statement A supply plane is flying at 60.0m/s at an altitude of 200.0m. What angle of flight will yield the maximum horizontal range for the dropped package? Homework Equations 1/2(g)(t)2. The Attempt at a Solution So far the only equations that i have, but may be wrong...

Homework Statement The 3.8-kg collar is released from rest at A and slides down the inclined fixed rod in the vertical plane. The coefficient of kinetic friction is 0.51. Calculate (a) the velocity v of the collar as it strikes the spring and (b) the maximum deflection x of the spring. I...

Homework Statement https://www.physicsforums.com/attachments/56019 Homework Equations The Attempt at a Solution The net force will be: F=\frac{2*Sin(\alpha)*q1*q}{(d/cos(\alpha))^{2}}=cos(\alpha)^{2}*Sin(\alpha)*qq1/d^{2} Taking the rerivative to find the maximum we...

Homework Statement http://img855.imageshack.us/img855/6951/captureaww.png Homework Equations The Attempt at a Solution Is one allowed to find R_{Th} by simply short circuiting all voltage source and opening all current sources and finding the equivalent resistance while keeping...

1. A hair dryer has a power rating of 1700 W at 110 V rms. Assume the hair dryer circuit contains only resistance. 2. The peak voltage is sqrt2 * rms voltage. 3. I got my esistance of the heating element is 7.12ohm and the rms current drawn by the hair dryer is 15.45A. But I am...

I'll spare you all the details, but suppose for some reason (too complicated to get into here) I needed to design a capacitor with certain fixed parameters and only one adjustable aspect, and I wanted the design to maximize the total charge the device could store. According to my calculations...

Homework Statement The line segment AB lies on a diameter of a circle of radius 1, and the angle BAC is a right angle. Find the greatest possible value of the sum of the lengths of AB and AC. Homework Equations The Attempt at a Solution I have no idea what parameters to use...

A human cannonball was fired from a cannon with a muzzle velocity of 107 km/h. The firing angle was 45 degrees from the horizontal Ive converted 107 km/h to 29.71 m/s 1.How many seconds did it take for the human cannonball to reach maximum height? 2.How high did he rise? h =...

Homework Statement John wants to measure the distance from his home to his office, so he drives to work several times and measures the distance on his car's odometer. Unfortunately, the odometer records distance only to the nearest mile. (Johns odometer changes abruptly from one digit to the...

Homework Statement This isn't homework, but I thought I would post it here as maybe more people would see it, and as I am not an engineer, it requires someone with more experience. The section is effectively an I beam with a hollow u shaped fitting along the top (see my rough sketch). I just...

Hello everybody. I have trouble of proving the theoretical maximum of heat pump Coefficent of Performance. The thing I'm trying to calculate is for heat pump pumping heat from colder reservoir to the hotter reservoir: COP=Qh/W Qh - heat supplied to the hot reservoir(output) W - mechanical...

Homework Statement I want to find the maximum value of x given that the differential equation relating x is: x' = 0.7548 - 599.49x^6 -2.4038x^2 - 0.12236x^1.5 Where x = 0 at t = 0. I have to do this with MATLAB using Euler's Method and here is my code: x = 0 a = 0 % initial t value b = 1000...

Basically I'm trying to find out how to find the maximum distance between two deuterium nuclei in order to overcome the coulomb barrier, causing them to fuse. Thanks

Homework Statement Suppose that two runners run a 100-meter dash, but the first runner reaches maximum speed more quickly than the second runner. Both runners maintain constant speed once they have reached their maximum speed and cross the finish line at the same time. Which runner has the...

Homework Statement A rocket, initially at rest, is fired vertically with an upward aceleration of 10m/s². At an altitude of .50 km, the engine of the rocket cuts off. What is the maximum altitude it achieves?Homework Equations V² = V_o² + 2aΔx t = (V-V_o)/a The Attempt at a Solution Well I...

A uniform simply supported beam, 5 m long and having a cross-section as shown, is to support a load which varies linearly from zero at the left hand support to a magnitude of 20 kN/m at the right hand support. Determine the position and magnitude of the maximum bending stress. ANS : 140 MPa...

(a) The steel cable to the hoist is 15m in length and has a diameter of 25mm. Its steel has a maximum permissible working stress of 200N/mm2 and a Young’s modulus of elasticity of 210,000N/mm2. The maximum load allowed on the hoist is 75kN. Determine the following:- (i) the cross-sectional...

Homework Statement (b) A steel alloy has an ultimate tensile strength of 820MN/m2 and a fatigue endurance limit of 390MN/m2. The steel is used in a fatigue application in which the alternating stress is 0.3 times the mean stress. Using the Goodman method with a factor of safety of 1.5...

Homework Statement The current-voltage characteristic of a photovoltaic energy converter (solar cell) shown in the attached figure can be approximated by: i = I_1(e^{v/V_{TH}} - 1) - I_2 where the first term characterizes the diode in the dark and I2 is a term that depends on light...

Homework Statement My Question paper is listed under attachement Question 2 Homework Equations M/I = σ/y The Attempt at a Solution My attempt at the solution is as per Q 2 attachment. What I am looking for is to see if I am on the right track. I'm worried that the units seem...

Homework Statement L=52 in A=2.76 in^2 E=10.4*10^6 psi Homework Equations σ=F/A ε=σ/E δ=εLThe Attempt at a Solution 4) σAB = (3P)/A ε=(3P)/(AE) δAB=(3PL)/(6AE) → δAB=(PL)/(2AE) solving for P P=[0.17*2*2.76*(10.4*106)]/52 → P=187680 lb → P=187.7 kip 5) Because AB and CD are in tension i...

The position of a mass m = 28.0 kg is given in by x(t) = 3.0sin ((15.0)t). Calculate the magnitude of the maximum force acting on the mass. F=ma. I tried deriving x(t) twice to get the acceleration equation so i could plug it into F=ma and then pick a random number for t. I chose t=1 but i...

Homework Statement (These may not be the exact wordings as it was asked by my friend and I do not have the exact question) Find the value of n for which a_n is maximum where a_n=\frac{1000^n}{n!} (Ans: n=999) Homework Equations The Attempt at a Solution I don't think using...

How do you calculate the acceleration and the maximum range of a jump (in this case a frog,) when the maximum vertical hight is 0.28m and the distance of acceleration is 0.086 m? I also tried to use the 45 degree, and the gravitation constant 9,81 m/s^2 but can't get it right..

Say given a simple acyclic directed graph with n nodes , which includes a starting node s0 and ending node e0 (i.e., a kripke structure without loop) what is the maximum number of path from s0 to e0?

Hi, This is not related with a specific homework question. I was studying this topic and have noticed that I didn't understand some bits.The car is negotiating a bend with a speed of V. The slope of the banket is θ The coefficient of friction is η Weight of the car if mg Radius of the bend is R...

A 534 g mass is connected to a light spring of force constant 6 N/m that is free to oscillate on a horizontal, frictionless track. The mass is displaced 2 cm from the equilibrium point and released from rest. What is the maximum speed of the mass? What is the maximum acceleration of...

Hi guys, have been struggling with this exercise, could anyone give any help? thank you so much!

Homework Statement Superman is regaining his strength by pulling with a force F on a large block of mass M resting on a frictionless floor as shown. A small block of mass m rests on the upper surface of the large block, and there is friction at that surface, with static coefficient μ. Lois...

A light rope fixed at one end to the wooden clamp on the ground passes over a tree branch and hangs on the other side. It makes an angle 30° with the ground. A man weighing 60 kg wants to climb up the rope. The wooden clamp can come out of the ground if an upward force greater than 360N is...

Homework Statement A perfectly elastic spring is attached to the ceiling and a mass m is hanging from the spring. he mass is in equilibrium when the spring is stretched a distance x(o). The mass is carefully lifted and held at rest in the position where the string is nether stretched nor...

Hi, I am trying to solve a problem but I can't figure how to continue.. There's an object moving in a circular path with radius 0.5m in an horizontal surface. The rope will break if the tension exceeds 16N. What is the maximum kinect energy? So r = 0.5m T = 16N K=\frac{1}{2}mv^{2}...

Hi, Homework Statement I was asked to show that if f''(x)>0 for every x in [a,b], then f has a maximum at either a or b. Homework Equations The Attempt at a Solution The book proves it thus: If f has a sationary point in [a,b] then that point must be a minimum, as f''(x)>0...

Dear physics, I'm new to the site. I found it reading this topic: https://www.physicsforums.com/showthread.php?t=145043 I wonder if we could manage to answer, if some not critical precision, the question of: How many people can live confortably, eating only potatos, in earth? As of...

Is there any maximum temperature that could be reached ( since temp is directly prop. To average kinetic energy , knowing that no particle can exceed the speed of light .

Assume you have a weightless constant volume container "filled with" vacuum. If you let it float in the atmosphere, how "high" would it go? I guess at some point Archimedes' principle should fail. What do you think?

Homework Statement Homework Equations Force = Current * Length * Field Strength * sin(theta) (Force/ Length)/(Current * sin theta) = Field Strength The Attempt at a Solution (.28 N/m)/ (14 A * sin 27 degree) = .044 T or 44mT