Physics homework Definition and 298 Threads

I need help on this question for my postlab, thanks ! By direct substitution, show that equation (3) is a solution of the differential equation (2) α(t)=α0 cos(√(g/l) t) (3) (d^2 α)/(dt^2 )=-g/l α (2) α = angle alpha in degrees α0 = amplitude of motion g =...

Hi, this is my first time using this forum, so i have no idea if this is even the correct place to be asking for help. I have a problem with my High School Higher Physics Homework. The question is as follow : Homework Statement During one run, a car and passengers of mass 800kg are released...

Homework Statement Here is the picture: I have an upcoming test, and I cannot seem to get any questions like this one. Help is greatly appreciated. I calculated the net force, such that Fnet=ma. There exists a magnetic force due to the current in the wire. The mass m is negligible, ie...

Homework Statement A golf ball is hit with a velocity of 50 m/s. The angle to the ground is 17 degrees. find t Homework Equations The equation my teacher provided was: y=vi(sinθt)-4.9t^2 The Attempt at a Solution 0= 50sin17-4.9t^2 0=-4.9t^2-48.1t this is where i got...

Hey guys, I am new to the forums. I am currently taking AP Physics in my senior year of high school, and I am having some difficulty solving the following two problems: 1. A ball is shot upward with a velocity of 30ft/s. Another is shot upward a second later at 100ft/s. Where and when do they...

need your help!physics homework Homework Statement [/b] A boron nucleus has mass 8.5e-27 kg. If its speed || is 0.961c (that is, ||/c = 0.961), what are the following values? particle energy = 2.767e-9 J rest energy = 7.65e-10 J kinetic energy = 2.002e-9 J Next an electric...

Assuming that the human body can survive a maxi- mum continuous acceleration of 6.40 m/s2, calculate the mini- mum time in which a spaceship can accelerate from 0 m/s to 3.0× 107 m/s, that is, to a velocity that is 10% the velocity of light.

Homework Statement A stone hangs by a fine thread from the ceiling and a section of the same thread dangles from the bottom of the stone. Homework Equations a. If a person gives a sharp pull on the dangling thread, where is the thread likely to break: below the stone or above it? b...

At t = 0, an object is projected with a speed v0 = 35 m/s at an angle q0 = 20.6° above the horizontal. For parts a-g, calculate the requested quantities at t = 10 s into the flight. (Use 9.81 m/sec2 for g.) a) The vertical acceleration of the object: I got -9.8 m/s2 b) Its horizontal...

Homework Statement Sally sue and her partner hold a spring 4 meters apart. There were 5 nodes in the standing waves produced. Sally moved her hand from the rest position back and forth along the floor 20 times in 4 seconds. F Homework Equations The Attempt at a Solution Since...

Homework Statement What is the power needed to change the speed of a 1600 kg SUV from 15.0 m/s to 40.0 m/s in 4.0 seconds The Attempt at a Solution I know that P = W/t and W = F/d, but I feel like there is not enough info to use this equation. Am I missing something?

So a factory whistle emits a sound at 875Hz. The temperature of the air is 25.9oC. What frequency will be heard by an observer in a car traveling at 27m/s away from the source i know this is a two step problem but i have no idea where to start! anyone lead me in the right direction?

Homework Statement A car weighing m kg, and a truck, weighing 4m kg, collide at an angle of alpha. Initially they are traveling at the same velocity. After the collision they move off together at an angle of theta. a) show that tan(theta) = (4 sin alpha) / (4 cos alpha + 1) b) Show...

Homework Statement A weather balloon is designed to expand to a maximum radius of 26m hen in flight at its working altitude where the air pressure is .026 atm and the temperature is 229K If the balloon is filled at atmospheric pressure and 434K, what is its radius at lift off...

Homework Statement The rotor (flywheel) of a toy gyroscope has mass 0.150 kg. Its moment of inertia about its axis is 1.20*10^- 4 kg m^2. The mass of the frame is 2.70×10−2 kg. The gyroscope is supported on a single pivot with its center of mass a horizontal distance of 4.00 cm from the...

Well at school we are doing an experiment to find out the factors which affect the distance between the lens and the image. Well I did the convex lens experiement and from my results i plotted a graph which is y vs x The distance between the lightbulb and lens is x and the distance between...

Certain particle moving with velocity v in a sitema O; its direction forms an angle μ with the axis X. To determine the corresponding angle in the system X´ which moves with velocity V over the system or in the positive direction of X axis if the X and X´ match.

Homework Statement 2.9 cm3 of water is boiled at atmospheric pressure to become 5271.2 cm3 of steam, also at atmospheric pressure. Calculate the work done by the gas during this process. The latent heat of vaporization of water is 2.26 × 106 J/kg . Answer in units of J. (part 2) Find the...

Please consider the following case: Spring connected at both ends by some masses.Everything is ideal. Find the extension of the spring. http://img101.imageshack.us/i/unledpi.jpg/ http://img101.imageshack.us/i/unledpi.jpg/ My big question is ...if the spring extends by a length say...

Here is the question. http://i72.photobucket.com/albums/i195/eloiamb/2011-04-2995015008.jpg Here is my solution to part a. http://i72.photobucket.com/albums/i195/eloiamb/physics.jpg I feel pretty confident but, some reassurance would be great. Maybe I'm just thinking to complicated but...

Homework Statement A) The wavelenght of an electron in an electron microscope is 0.0122nm.What is the electron velocity? B) Sodium lights emit light of yellow colour, with photons of wavelength 580nm. What is the energy of these photons? Homework Equations v=w/k k=2pi/wavelenght w=2pi*f...

Homework Statement A radioactive material decays by simultaneous emission of two particles with respective half-lives t1 and t2. If the material decays by the emission of the particle with half-life t2 only, then the time in year after which 1/4 th of the material remains is. (Given t1=1620...

Homework Statement 10% of a boat sink in water when it is float, from its total volume. 70% of its total volume sinks, when 1200kg loaded into it I) Calculate the mass of boat. II) The boat totally sink due to a hole in bottom of it, with that 1200kg load, with a uniform rate of 100kg of...

Homework Statement A uranium nucleus (X=92) splits into two equal fragments, and each has a radius of approximately 8x10^-15m. What is the Coulomb potential energy of such fragments when in contact? Homework Equations I tried using the coulomb law but that doesn't work. Could it be to do...

Homework Statement #56 Homework Equations index of refraction = sin(Θincident)/sin(Θrefraction) The Attempt at a Solution yeah i think Θincident is 30 degrees but i don't know how to solve for Θ of refraction. sorry, my teacher didnt teach me optics yet, and she assigned problems...

Homework Statement http://img26.imageshack.us/f/1113001.jpg/ #16 Homework Equations P=F/A The Attempt at a Solution F= 30N A= πr^2 r= .01m A = .0001π P=F/A P= 10^3 Pa but the answer is E) 10^5 Pa

Homework Statement A 10.0 length of wire consists of 5.0 of copper followed by 5.0 of aluminum, both of diameter 1.3 . A voltage difference of 87 is placed across the composite wire.What is the total resistance (sum) of the two wires? Homework Equations R=pL/A The Attempt at a...

In the attached notes, there is a paragraph on p61 just under the eqn \dot{R}^2=\dots that explains why inflation solves the flatness problem. Can someone explain to me how this works please? I cannot get my head around it...

Homework Statement capacitor blocks Direct current. but how can a battery which is a source of direct current charges a capacitor. Homework Equations The Attempt at a Solution

Homework Statement Consider a circular loop with resistance R. Perpendicular to the loop there is a magnetic field B(t) = t, where t is the time. If a voltmeter is connected to two points on the loop separated by 90 degrees, what would it show? The Attempt at a Solution the answer...

Homework Statement A 19-cm-long nichrome wire is connected across the terminals of a 1.8 V battery. If the current in the wire is 2.1 A, what is the wire's diameter in mm? Homework Equations R = Rho*L -------- A v=ir The Attempt at a Solution rho for this = 100...

1. Consider a projectile, which is thrown at an angle of  with an initial velocity of v0.  a) For a fixed angle, and the maximum height.  b) Calculate the distance it travels before returning (gently, of course) to the ground (which is assumed to be flat).  c) Use these pieces of...

1PHYSICS KINEMATICS HELP? President was shot while at home. While sitting on the sofa near the window, one bullet came through the window and grazed the president's thigh. The CID rounded up 4 suspects : A. B, C and D. All four were found with a rifle. Forensic scientists have concluded from...

Thanks for the help, sorry I am not really good with Physics and i could use some help please. Homework Statement A sailboat is being propelled westerly by the wind at a speed of 4m/s. If the current is flowing at 2m/s to the northeast, where will the boat be in 10minutes with respect to its...

Hello everyone! I'm having a problem with this question from my book... How many electrons have been removed from a positively charged electroscope if it has a net charge o 7.5x10^-11 C? Can someone explain to me how to solve this problem>? Thank you very much!

Homework Statement The circle inside the large square below has an area of 47.4 cm2. http://tinyurl.com/PhysicsSquare Calculate the area of the large square. Note that the circle passes right through a number of grid intersection points.Heres the help the professor gave...

physics homework help please projectile motion Homework Statement a biker is iding on a flat stretch of lan 50 m long, without friction. he then goes up a flat ramp that its surface is 30 degrees from the ground (no friction) the biker then leaves the ramp and goes 37.5 m across to the other...

Homework Statement A compressed spring is released pushing a block at rest along a level, frictionless path. This is Location 1. The block then passes over a small area of friction which ends and becomes frictionless again. This is Location 2. The block then enters a loop-the-loop in the...

Hello, I have solved the following problem but my answer does not matched with the answer which is written in the book. My answer is 32 m/s but the answer of the book is 37 m/s [PLAIN]http://img842.imageshack.us/img842/6706/projectile.png Could anyone please show me where my mistake is...

The Advanced Physics Homework Help forum is for upper-division (college junior or senior) and graduate-level questions. Other schoolwork physics questions should go in the Intro Physics forum. Thanks!

Homework Statement After falling from rest from a height of 34 m, a 0.47 kg ball rebounds upward, reaching a height of 24 m. If the contact between ball and ground lasted 1.8 ms, what average force was exerted on the ball? Homework Equations vf^2=2gh vf=sqrt 2gh...

Hey guys I am completely stuck and have no idea where to start. Help? Homework Statement Car A and Car B collide in an elastic collision. Use the data in the table shown to calculate the maximum compression of the car bumpers. The spring constant of the car bumper is 60 000 N/m. Assume...

Homework Statement Hi I am not too sure but I had my physics exam the other day.I think it went great although I am much confused on few problems now when I come to think of them.Question first asked for me to find kinetic energy of a photon. So using 1/2mv^2 I got that value later on it...

I have a question here that I'am completely lost on. A mass was moving clockwise around a circular path when a multiflash photograph was taken of its movement. The camera had a flash frequency of 1Hz ( 1 flash photo per second), and a photo similar to the diagram below resulted. (a)...

Physics help - I know that this qn may be easy but pls help!? Homework Statement A motorist was driving along a level road at a steady speed. He had to brake as quickly as possible to avoid a collision. The motorcycle decelerated uniformly at 7.0m/s2 and stopped in 2.0s. a) At what speed...

Homework Statement A 1750-N irregular beam is haning horizontally by its ends from the ceiling by two vertical wires (A and B), each 1.25m long and weighing 2.50N. The center of gravity of this beam is one third of the way along the beam from the end where wire A is attached. A) If you pluck...

Homework Statement Please I am just going to list the question then show my solving, It is a physics question but I need help on integration, on parts of the question, thank you quesiton: A particle in the infinite square well, (i.e V(x) = \left{ \begin{array}{ccc} 0 & \textrm({ if 0 <= x <=...

Homework Statement If a designer finds through research of accident reports at a hospital that children under 5 can usually survive a fall of 1 m without serious injury, what is the maximum safe turning speed for a carousel to be used by children of this age? Homework Equations No Idea...

At my University, we get (in Experimental Physics) weekly homework which consists of three exercises with 3, 3 and 4 points (thus giving a total of 10 points for each sheet). Now I have received the sheet for the next week, on which the third task is "Oil Drop in an electric field". The first...

I've been out 8 days and i missed this entire chapter, with a test on monday so I am trying to get all caught up. but i don't know how to do any of this homework. Homework Statement the mass is 3.80 kg, T = 16 N, and = 35 degrees. The surface has no friction. If x is horizontal and y...