Homework Definition and 998 Threads

Homework Statement an object of some mass, m, is accelerated upwards (from rest) off the surface off the Earth for some unknown time, t. At the end of this time, the object is traveling at some new speed, x. Derive the following formula. That is, show that no matter how much time the rocket...

Homework Statement I have a rope held by a hook, which is attached to the ceiling by a chain (with an angle theta), in one side, the rope (with an angle alpha) is attached to a a wall, in the other side, the rope is carrying an anvil of 110 Kg mass in vertical position. What is the tension in...

Homework Statement an electron with a speed of 5x10^6 m/s is injected into a parallel plate apparatus, in a vacuum, through a hole in the positive plate. The electron collides with the negative plate at 1x10^6 m/s. What is the potential difference between the plates? Homework Equations...

I have a question in my book and it’s confusing me a bit. I tried to search online for similar solved problems but couldn’t succeed. So here it goes:Calculate the induced EMF in a conductor loop when the angle between \vec{A} ~ and~ \vec{B} ~is~ changed ~from ~{0 °}~ to ~{α °} in 1 second...

Homework Statement Please look at the photo! Homework Equations -x^2+4x=x^2-6x+5 The Attempt at a Solution I got 2x^2-10x+5 but it says it's wrong

Homework Statement A boy fishing on the jetty observes water waves coming in from the ocean. He sees 4 waves pass him by in 2 seconds, each with a wavelength of 0.5m The speed of the waves is? Homework Equations v=d/t The Attempt at a Solution 4 waves pass him in 2 seconds. 4waves x 0.5m...

A star is 3.7 x 104 ly (light-years) from the center of its galaxy and is moving in a circle around that center at a speed of 170 km/s. (a) How long does it take the star to make one revolution about the galactic center? (b) How many revolutions has the star completed since it was formed about...

Homework Statement [/B] There is lead XY shaped as straight wire. Next to it, circular lead with radius 0.10 m. They are in the same plane. XY to center of circle, O is 0.20 m. Curent flowing through XY is 15.7 AHomework EquationsThe Attempt at a Solution 1) find magnetic field (B) at O[/B]...

Hello. I have an assignment to submit and I really want to get full marks/know where I went wrong If anyone has a tiny bit of free time would you mind please checking my homework? Even if you just check 1 page I will be so grateful. Thanks again https://imgur.com/a/rHVdjzn

Homework Statement [/B] An uncharged nonconductive hollow sphere of radius 10.0 cm surrounds a 20.0 µC charge located at the origin of a cartesian coordinate system. A drill with a radius of 1.00 mm is aligned along the z axis, and a hole is drilled in the sphere. Calculate the electric flux...

Homework Statement I've spent at least 1.5 hours on this problem trying to figure out what i did wrong and I can't find anything. With an exam in two days plus another chapter to go through. Regardless, here are the problem(6) and answer, as well as my work. Hope you can read it, and the...

A steel washer is suspended inside an empty crate from a light string attached to the top of the crate. The crate slides down a long ramp that is inclined at an angle of 37 above the horizontal. The crate has mass 154 kg. You are sitting inside the crate; your mass is 61 kg. As the crate is...

Homework Statement Homework Equations [/B]The Attempt at a Solution I soled for the integral of the magnetic field but i don't know what bounds to intergrate over and also i what is DS in this case? its a point charge so shouldn't bio savart have q(v*b) instead of i(ds*r)?[/B]

Homework Statement A 1450-kg car is towing a trailer of mass 454-kg. The force of air resistance on both vehicles is 7471N[backward]. If the acceleration of both vehicles is 0.225m/s^2[forward], what is the force of static friction on the wheels from the ground? Homework Equations Fnet = ma...

Homework Statement Mohrs circle question - https://imgur.com/SKeTUXN Shear stress in I beam question - https://imgur.com/34yTyCAHomework Equations Mohrs Circle - None Shear stress in I beam - I = d . b^3 / 12 tmax = (F / I . b) . (A1 . y1) + (A2 . y2)The Attempt at a Solution For the...

Homework Statement A capacitor with initial charge q0 is discharged through a resistor. What multiple of the time constant τ gives the time the capacitor takes to lose (a) the first 1/8-th of its charge (b) 7/8-th of its charge? Homework EquationsThe Attempt at a Solution since ı know...

Hey, I am a physics major and a new semester is about to begin. I think my biggest problem study wise is that I would go over the lecture notes and sometimes the textbook too, yet always feel ill equipped to tackle the homework problems. Currently my strategy is to go over the text...

Homework Statement I am giving the following signal: and asked to get the DSB-SC signal of this Homework Equations 3. The Attempt at a Solution [/B] So, I know a few things. My prof writes that I would have to multiply my original signal out and then take the Fourier transforms...

Homework Statement Nikhil is probably eating his daily snack at this time. Old Man Miller comes back from the store and takes the 0.150kg sandwich from Nikhil as he begins to run away. Nikhil is running at 7.5m/s away from me when I hit him in the head with the sandwich that was moving at...

Homework Statement Mariana is volleying with Old Man Miller and returns one of his feeble tennis serves. He serves the ball such that it is moving at a speed of 35km/h [Forward] when she strikes the 0.060kg ball and sends it back over the net at a velocity of 55km/h[Backward]. a) If the ball...

Homework Statement Consider 2 balls A,B on the same line . and they are connected to a third one G with a rope L. AG, AB. now the system monves in the effect of the mass of G and its projection to the line AB is in the middle. No friction. mass of A=mass of B=m and mass of G=2m .FInd the time...

Homework Statement Consider 2 balls A,B on the same line . and they are connected to a third one G with a rope L. AG, AB. now the system monves in the effect of the mass of G and its projection to the line AB is in the middle. No friction. mass of A=mass of B=m and mass of G=2m .FInd the time...

Homework Statement Identify the type of filter (kinds of frequencies the circuit filters out) analytically 2. The attempt at a solution I believe the top filter to be an inverting low-pass filter, which passes lower frequencies and blocks higher frequency signals. I also think that the...

Homework Statement Show that ##4\pi G(\dot \phi)^2=\epsilon a^2 H^2## Homework Equations Over dots mean derivative with respect to ##\eta##. $$\frac{1}{a}\frac{d}{d\eta}=\frac{d}{dt}$$ $$H=\frac{\dot a}{a^2}$$ $$\epsilon=\frac{-\dot H}{aH^2}$$ $$(\frac{\dot...

Homework Statement Consider the system of two large, identical Einstein solids, each with oscillators, in thermal contact with each other. Suppose the total energy of the system is 2 units of the energy quanta, i.e., =2ℏ, (i) how many MACRO-states (e.g., one macro-state corresponds to one...

Homework Statement A wave pulse on a string is given by D(x) = D[0][/SUB]/(x[2][/SUP]+a[2][/SUP]), where D0 is a constant with units of cm3 and a is a constant with units of meters. a. If the wave moves along the string at a velocity of v in cm/s, what is the transverse velocity of particles...

Homework Statement A taxi car weighing 2000kg hits a stationary mini-van that has a mass of 2200kg. The taxi stops and the mini-van rolls and hits a stationary sports car with a mass of 1830kg. Their bumbers hit and they move together at 2.3m/s. What is the velocity of the taxi before the...

Homework Statement Three insulated concentric spherical conductors, whose radii in ascending order of magnitude are ##a, b, c##, have charged ##e_1, e_2, e_3## respectively, find their potentials and show that if the inner most sphere is grounded, the potential of the outermost is diminished...

Homework Statement The general goal of the problem is to derive some useful identities involving the slow-roll parameters during inflation. For part a show that: $$\frac {d} {d\eta} (\frac {1} {aH})= \epsilon - 1$$ Homework Equations $$\epsilon \equiv \frac {d} {dt} (\frac {1} {H})= \frac...

Homework Statement Write down the equations of motion and develop the continuous-time system. Homework Equations See my word doc. or PNG's. The Attempt at a Solution See my word doc. or PNG's. I assumed that there was no friction as no information was given. I can easily get the transfer...

Hello users, Im a boy whos in high school and has physics as a school subject. I'm not the best in physics at all and next week I'm going to have a 3-chapter test about physics. The teacher gave us some practice material and I struggle with this question, anyone that could help me? 1. Homework...

I was just wondering if there was any proof that the medieval period had more conflicts like wars etc. but with less (peace) negotiation between parties than now? Thanks so much!

Homework Statement True or False: 1.Equipotential surfaces intersect: 2.Electric field lines are found within equipotential surfaces: Homework Equations E=Vd The Attempt at a Solution 1. I think this is false since the same reasoning describes why electric field lines don't intersect 2. I'm...

I'm taking an AP physics course on the edx.org platform and I arrived today at the "Forces" Unit. One of the fundamental properties of force that it's equal to acceleration times mass, but I, as a curious stubborn nerd, always look for the "why's", so I thought to myself "why it's not equal to...

A rod of mass M (=4m) and length L is placed over a smooth horizontal table. One end of rod is attached with a block of mass m through a light string as shown in the figure. The pulley is friction less and light. the acceleration of com of rod at the given instant is (g = acceleration due to...

I’m trying to calculate how hard someone throws a ball. I know that F=ma, but the only force acting on a ball is the force of gravity and so the equation simply cancels out.

Homework Statement Find number of fringes separated by 1 cm on a screen at a distance of 2mm from slits which are 0.2mm apart from each other.The wavelength of light used is 500nm. Homework Equations The Attempt at a Solution I really don't know any way to solve it.I have tried putting unit...

Homework Statement I have the following variables: f = .93 m f(e) (eyepiece) = .0082 m distance toJupiter pj = 588 E^9 diameter of Jupiter dj = 139822 E^3 Find the height of the image of Jupiter created by the objective lens of a telescope. Homework Equations M = -q/p q = f Where M is the...

a) dimension the moving-coil movement so that it indicates full deflection at 25 V given Values: Voltage Source: U2Max = 25V; moving-coil movement: IM = 100µA; UM = 270mV Rv = ( U2Max - UM ) / IM = (25V - 270mV) / 100 µA = 247,3kΩ b) the internal resistance is increased by 20 %...

Homework Statement Consider following transformation: Transformation: $$X^{\mu}\rightarrow \tilde{X^{\mu}}= X^{\mu}+\xi^{\mu}(\eta, \vec{x})$$ where ##\xi^0=T, \xi^i=L_i## Show transformation of metric perturbation ##B_i\rightarrow \tilde{B_i}=B_i+\partial_iT-\partial_{\eta}L_i## Homework...

Homework Statement Homework EquationsThe Attempt at a Solution [/B] As this is an indeterminate structure with degree of redundancy 2, I have released support B & C. I then draw the BMD M0 of the Primary structure as well as BMD m1 and m2 of unit load system acting on B & C as follow: I...

Homework Statement Steam is expanded from 90 bar, 412°C to 4.0 bar saturation in a high pressure turbine, after-which a certain percentage of the steam is bled off to a feed heater. The remaining steam is then expanded through a low pressure turbine to 1.0 bar and dryness fraction of 0.93. All...

Suppose that X, Y are uncorrelated random variables which are each measurements of some unknown quantity $\mu$. Both random variables have $\mu_{X} = \mu_{Y} = \mu$, but $\sigma^2_{X} > \sigma^2_{Y}$. Determine the value of $\alpha$ in [0, 1] which will minimize the variance of the random...

A machine consists of two components whose lifetimes have a joint density function: $f(x,y) = \left\{ \begin{array}{ll} \frac{1}{50} & \quad x \geq 0, y \geq 0, x+y \leq 10 \\ 0 & \quad Otherwise \end{array} \right.$ The machine operates until both...

Homework Statement Homework Equations The answer in the book is (4F(L^3))/3EI The Attempt at a Solution I felt the above question could be simplified into a standard beam problem. I choose the following beam. I used the Yc equation, but when I replace a with L I get an answer of...

So here is a thing. If I get at least 6/10 questions in this homework I will get 100% in this semester's homework which is equivalent to 20% of the maths module. So could you double check these questions? Also I wouldn't mind some help with q.3 I got a weird answer of 11,8 billion. Workings...

Homework Statement Place a book flat on a table and press down on it with your hand. Now suppose the hand-book and table- book values of are 0.50 and 0.40, respectively; the book's mass is 0.90 kg and your downward push on it is 10 N. How much horizontal force is needed to keep the book moving...

Homework Statement A crate is being transported on a flatbed truck. The coefficient of static friction between the crate and the bed is 0.470. What is the minimum stopping distance if the truck, traveling at 70 km/h, is to decelerate uniformly and the crate is not to slide forward on the bed...

Homework Statement A worker is going to attempt to pull a 90-kg box across a level floor by a rope that makes an angle of 35° with the floor. The tension in the rope is gradually increased until the box just starts to move. If the coefficient of kinetic friction is 0.36 and the coefficient of...

Homework Statement An 82 kg man inside a 40-kg dumb-waiter pulls down on the rope. At that moment the scale on which he is standing reads 209 N. Determine the elevator's acceleration. Homework Equations F=ma The Attempt at a Solution I know the acceleration is 0.152 m/s^2 upwards , I need...