Hard Definition and 1000 Threads

hard kinematic problem, need...help...pls:) Homework Statement A policeman (on a motorcycle, with the engine going) is hiding behind a bush on the side of the road when a speeding truck passes with a speed of 96.5 km/h. As the truck passess he sets off with an acceleration of 1.83 m/s, which...

Homework Statement Solve the equation: cos2x - sinx = (1/2) for [0,2pi). Homework Equations sin^2x + cos^2 = 1 The Attempt at a Solution cos^2(2x) - sin^2x = 1 1 = 1 Infinite Solutions?

I am trying to prove that the Limit as p approaches infinity of {integral from 0 to 1[|f(t)|^p dt]}^(1/p) is in fact equal to the max of |f(x)| between [0,1]. Any suggestions I am sure I need to set the limit to less than or equal to and greater than or equal to the max but i don't quite...

kinematic question, i think it's hard:( Homework Statement Two camels leave the spinx at time 52.5 s apart. The first moves off with a uniform acceleration of 1.30 m/s2, which it maintains for 1.92 s. It then continues with the acquired speed. The second camel moves of with a uniform...

I'm just wondering why PMMA (polymethylmethacrylate) is hydrophobic and does not attract water. I can't find anything that explains this on a molecular level :S

So my computer is just over 1 year old. I put it on sleep a lot rather than shutting it down (but I don't think this hurts the hard drive). Is there any reason for worry? According to HD Sentinel, the percent health is 88%. According to "Failure Trends in a Large Disk Drive Population", my hard...

Homework Statement Evaluate: \int\int \phi \nabla(\frac{1}{R}) - \frac{1}{R}\nabla\phi * \vec{n} dS a) over the surface of the ellipsoid 1/9\,{x}^{2}+1/16\,{y}^{2}+1/25\,{z}^{2}=1 > where \phi={x}^{2}+{y}^{2}-2\,{z}^{2}+4 Homework Equations The Attempt at a...

!Desperate!This Dynamics Problem is Killing ME! Homework Statement We have ben dealing with General Plane motion of a rigid body and this problem has been getting the best of me for some time now I know from the text that the answers are \omega_a=14 rad/s \omega_b=28.8 rad/s and...

and theoretical science: I have somebody I want to set straight about the difference between unproven theories: and proven hard science that is used daily. The answer coming from a real scientist or engineer will have more of an impact then coming from me. Can anyone here give a lucid...

!For The Love of GOD! Diff Eq Homework Statement I have done this problem 3 times. I am getting a sign error somewhere and I cannot find it. When I solve this DE and then plug it back into the original, it is not checking out! Can anybody see my error? I would really appreciate a second...

\frac{5x-5y-bx+by}{5x-5y+bx-by} i can't cancel anything i can't factor anything please help

hi, everyone. Do anyone here can suggest where, which book or website can learn more bout the theory behind the magnetic hard disk, and it current technology? i.e. spintronic...

This is my first post and while I have more degrees than a thermometer none af them have anything to do with this forum. However, I love cosmology and have a few questions from the untrained perspective. I have written and published that the obvious is often the most difficult to see. I have...

[SOLVED] Forces, Acceleration...Hard Stuff (HELP!) A trailer with loaded weight Fg is being pulled by a vehicle with a force P. The trailer is loaded such that its center of mass is located as shown. Neglect the force of rolling friction and let a represent the x component of the...

Alright guys here it is: My teacher asked us to think about a bonus question. He wants us to use torque to find the mass of the sliding mass on the center beam balance (the one that moves through 0,100,200...ect.) How do i do this?!

Problem with Work Done by Friction, Velocities--Extremely Hard Homework Statement Here is the known data: The track has to be 1500m max, less track can be used. There is a minimum of 3 hills (you decided how steep and how high they are). There are two turns (track makes one lap). The...

Some time ago I was wondering about disconnecting my alternator from my race car just during a quarter-mile drag run. The lesser friction on the motor's drive belt system would be ideal. Then I realized that spinning the alternator itself is not that much of a problem, it spins pretty freely...

Let's say I have a one-kilogram object, and I drop it from heights of 1 meter and 2 meters, respectively, ignoring air resistance/friction and so forth. Are the following statements true? The objects hit the ground with the same force since the mass and acceleration (due to gravity) do not...

Does anyone know of any programs/methods for this? I had a disk crap out on me over the weekend and there are some email I didn't have backed up that I would like to try and recover. I tried repairing it with chkdsk and the Windows Recovery Console to no avail. Thanks...CS

Problem Determine the differential and total cross sections for scattering from a "hard sphere" of radius R ("hard" means impenetrable). Relevant Formulae \sigma (\Omega) d \Omega = \frac{number \ of \ particles \ scattered \ into \ solid \ angle \ per \ unit \ time}{incident \ intensity}...

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Homework Statement Prove that Neither <xp>=∫ψ* x(ħ/i)(∂/∂x) ψ dx nor <xp>=∫ψ* x(ħ/i)(∂/∂x)xψ dx is acceptable because both lead to imaginary value.Show that <xp>=∫ψ* x(ħ/i)(∂/∂x) ψ dx + ∫ψ* x(ħ/i)(∂/∂x)xψ dx leads to real value.Does <xp>=<x><p> ? Homework Equations...

Consider triangle ABC,the continues charges distribution lies on the side of BC with the linear charge density such as m,prove that the direction of electric force in the point A lies on the bisector of the viewing angle BAC

someone pls help A worker bee is ready to fly out and gather pollen, but on her way out of the hive she meets a fellow bee worker who tells her there is a pollen source 0.3km southeast of the hive. however, before the outgoing bee leaves the hive, she meets another incoming bee and she tells...

Hard Motion Question- Help? I am really stuck on this motion question, can anyone help please?:confused: "A balloon is 30.00m above the ground and is rising vertically with a uniform speed when a coin is dropped from it. If the coin reaches the ground in 4.00 seconds, what is the speed of...

I am hot but I need fire, I am tall but I need to jump, I am long but I need to stretch and I am slimy but I need slime, I am full but I need fuel. I end in X. What am I?

Evaluate and express as a fraction in lowest terms -3 to the power of 4 + (-3)to the power of 3 - (-3)to the power of 2. (I apoligize...I don't know how to type powers on the computer...>_<) I tried to evaluate it like it told me to...so I ended up with 81-27+9 =63 Yet when I...

A pump, submerged at the bottom of a well that is 35 m deep, is used to pump water uphill to a house that is 50 m above the top of the well. The density of water is 1000 kg/cm^3. All pressures are gauge pressures. Neglect the effect of friction, viscosity. A) REsidents of the house use .35...

Well the top keys on my TI are really hard to press, I obviously spilled something but do not remember. Is there a way to make them easy to press again? It's getting really annoying :-[

I am trying to write a position vector for point D I originally thought that the z component was 0...but now common sense is telling me that it can't be...the rope must be sagging. Are my first to components correct or am I visualizing this incorrectly? : 8i+7j-(something)k <---or...

A baseball has a mass of about 0.14 kg, and it is pitched towards home plate at a speed of about 46 m/s. If the bat exerts an average force of 8900 N for 2.1 ms, what is the final speed of the ball in m/s?

A block of mass m = 0.900 kg is fastened to an unstrained horizontal spring whose spring constant is k = 94.5 N/m. The block is given a displacement of +0.120 m, where the + sign indicates that the displacement is along the +x axis, and then released from rest. (a) What is the force (magnitude...

Homework Statement 14. Figure 28-36 shows a metallic block, with its faces parallel to coordinate axes. The block is in a uniform magnetic field of magnitude {0.020{\textcolor[rgb]{1.00,1.00,1.00}{.}}T}. One edge length of the block is 25{\textcolor[rgb]{1.00,1.00,1.00}{.}}cm; the block is...

Hard Wave Question (Really need help pleasez!) The Bay of Fundy, Nova Scotia, has the highest tides in the world. Assume that in midocean and at the mouth of the bay, the Moon’s gravity gradient and the Earth’s rotation make the water surface oscillate with an amplitude of a few entimeters and...

Homework Statement An oscillator with a mass of 420 g and a period of 1.00 s has an amplitude that decreases by 1.20% during each complete oscillation. If the initial amplitude is 8.20 cm, what will be the amplitude after 50.0 oscillations? If the initial amplitude is 8.20 , what will be...

hi, there is a challenging problem that no one could answer it,so here it is if anyone wants to try: if x,z,y are all positive real numbers prove that: (1+x^2)(1+y^2)(1+z^2)/(xyz)>=8 so anyone can help please? thank you.

Q1 A kangaroo was seen to jump to a vertical height of 2.8m. for how long was it in the air? Attempt on the solution not possible? what do you guys think? Q2 A ball was photographed stroboscopically as it was released and fell freely. eight images appear on the phto which is...

Im having trouble installing a new HD into my computer. Where can I found information, accurate and up to date, about: partitioning, formating, fdisk, MBR, , multiboot, ... thanks.

hard trig question :( Homework Statement A,B, and C are three vertices of a cube, as shown in the diagra,. Find the measure of <ACB, to the nearest tenth of a degree. this is the diagram of the cube http://img144.imageshack.us/img144/6396/dsdsddry9.jpg with no given side and angle how...

MiH had a cameo in my dream last night. A guy who lived next door to a place I was visiting was experimenting with the aerodynamics of antenna probes, firing them off his balcony to see which would travel farthest and stick in the ground best. All these spiky things were protruding from his...

Hard gravitational force problem! Homework Statement [/b] Derive an expression for the gravitational force between a sphere with mass m and another sphere with mass M and radius R, IF the sphere of mass M has a spherical hollow inside which touches the surface of the sphere and the center of...

Initially, a 2.00kg mass is whirling at the end of a string in a circular path of .750 m on a horizontal frictionless surface with a tangential speed of 5 m/s. The string has been slowly winding around a vertical rod, and a few seconds later the length of the string has shortened to .250 m...

I'm almost 25 years old and I've finally started going to college, for a bachelors in mechanical engineering. I feel like it's the perfect major for me: I love math and physics, and I love creating things. My only problem is that I'm not wild about the idea of having a 9-5 job, working 5 days...

Homework Statement Find d^2y/dx^2 in terms of x and y. x^2y^2-2x=3 Homework Equations property rule, chain rule, quotient rule, The Attempt at a Solution I can do this the long way, but there must be a shorter solution. Can I simplify it? I've found dy/dx=(-xy^2 +2x)/(2x^2y)...

Homework Statement How hard do you need to push a 2kg box which has .2 coefficient of kinetic friction so that it moves with a constant speed of 5m/s? [The Attempt at a Solution (I'm calling g 10m/s2 not 9.8) F(kinetic friction)=(.2)Fn=(.2)mg=(.2)(20N)=4N so...since the acceleration is...

ok so this is my first post and I am not sure if what I am looking for is even possiable or that I am even posting in the right form.. anyways im looking for a way to find the specific heat of a water sample depending on the hardness, i measure hardness with grains per gallon (gpg). and I am...

A Hard differential equation! Solve: dy/dx = (x^2) + y

Let's say you're running a Fortran program that writes to the hard drive. What happens when the hard drive is completely full? Do other files get written over?

Find all triples of primes (p,q,r), that pq+qr+rp and p^3+q^3+r^3−2pqr are divisible by p+q+r. I really don't know how to start, (of course I've been trying)

Homework Statement Un a sequence 0 < x < pi/2 U0 = 2cosx Un+1 = quroot( 2 + Un) 1) Calculate U1, U2, and U3 in function of x (simplify maximum) 2) Show that Un = 2cos( x / 2^n)Homework Equations The Attempt at a Solution 1) U1 = sqroot( 2 + 2cosx) = sqroot( 2 (1 + cosx)) = ?? (now , how...