Final Definition and 1000 Threads

I just finished the last final exam of my engineering undergrad and I know I did terribly bad. I am worried that I might fail the course and have to come back another year to gain credit in that one single course in order to graduate. If that happens, my parents will kill me. They are already...

Homework Statement find the position (r) when the vector comes to rest. Homework Equations initially velocity = 'u', acceleration = a u= -14i-7j a= 6i+3j The Attempt at a Solution hey guys I am new at this so i didnt know how to post it but some help would be great :) i tried...

If an object starts with an initial velocity of 0, and has a velocity of 1.07 m/s after 20 cm, what is the velocity at 1 meter, assuming a constant acceleration? I do not know how long it takes to travel the full 1 meter. All I know is that after 20 cm the velocity was 1.07 m/s and it took 177...

Suppose a projectile is fired upward from the surface of the Earth. If the initial speed of the projectile is v = 12.0 km/s (more than the escape velocity): how fast will it be moving it is so far from Earth that the force of gravity is approximately zero? The equation I was given to solve...

Homework Statement Show that \frac{d}{dt}\int \rho r^{2}\phi dr = \int \rho r^{2}\frac{d\phi}{dr} dr Homework Equations Fundamental theorem of calculus The Attempt at a Solution So I follow the derivation from the textbook and I think I get the rather sneaky rearrangement of...

Hi physicsforums mates, I came across an interesting application question online on optimal mass / velocity. The context was given that an object on wheels have to be released down a ramp of angle θ (assume to be anything). It has to travel a far distance after reaching the end of the ramp and...

Homework Statement Show that the exit intensity as a function of Io (intensity out of light source) and θ12 (angle of second polarizer compared to the first polarizer) is I = (Io/8) sin(2(θ12)))^2 Homework Equations Malus' Law I = Io (cosθ)^2 The Attempt at a Solution I1 =...

I have this assignment, basically I had to do the same thing in simplified way and then superposition theorem. Apparently the answers don't match. I'm pretty sure the mistake is in superposition theorem. It could be some really stupid and simple mistake I made since I'm no good at this at all...

1. The Question from Text: "A forest playground has a tyre hanging from a tree branch. The tyre behaves like a pendulum, with a rope of 4.0 metres length, and the tyres mass 15 kg. A child of mass 45 kg swings on the tyre by pulling it 3.0 metres to one side and leaping on. What is the maximum...

Homework Statement Using a value of n of 1.1, calculate the final pressure and temperature when the cylinder is compressed rapidly with a compression ratio of 15. Starting pressure = 101.325 kPa Starting temp = 298 K Homework Equations (V2/V1) = 15 The Attempt at a Solution...

The above diagram shows the problem description. I have to find the final temperature distribution after thermal equilibrium. I am assuming that the thermal energy is conserved but not the temperature.(Correct me if I am wrong) Energy of the materials at initial state is (Refer Image) For...

Homework Statement http://img812.imageshack.us/img812/1874/entropy.jpg The Attempt at a Solution First, not sure if this is an adequate explanation but I think for both gases in both partitions, regardless of whether it starts off colder or warmer, the total entropy will increase in...

Homework Statement A boy throws a rock off of a cliff that is 33m high. The rock weights 1 kilogram and it's inital velocity is 13.5m/s. It is thrown at an angle of 40° with the horizon. Initial Velocity = 13.5m/s mass = 1 kg θ=40° Δy = 33m g = 9.81 m/s^2 Homework Equations...

Homework Statement A spherical bowling ball with mass m = 3.2 kg and radius R = 0.112 m is thrown down the lane with an initial speed of v = 8.1 m/s. The coefficient of kinetic friction between the sliding ball and the ground is μ = 0.32. Once the ball begins to roll without slipping it...

Homework Statement A solid disk of radius 5m and mass 8 kg rotates clockwise at 1.5 rad/s. Above this disk is a hoop of radius 2.5 m and mass 8 kg , rotating counterclockwise at 3 rad/s. The hoop drops down onto the disk, and friction causes them to rotate together. Find the final velocity...

Homework Statement The Attempt at a Solution I used conservation of momentum for the initial velocity of mass 2, and conservation of mechanical energy for the movement from rest to highest position, KE=PE. The answer that I received is selected in the screenshot. However, when the...

Homework Statement A fiendish physics instructor devises the following exercise for students as a pass/fail final exam for their heat course. A 110 g cube of ice (5 cm on a side) is placed in a form fitting Styrofoam box that is 2 mm thick. The ice cube and the inside of the box are at a...

Homework Statement Mass m1=6kg traveling with velocity 4 m/s collides with mass m2=16kg traveling with velocity 3m/s in the direction shown (m2= is at an angle of 60degress). If the two masses stick together, find the final velocity of the combined masses, and the kinetic energy lost...

Hi all, I am studying for a BEng degree in motorsport engineering in the uk. I am planning to continue on to the MEng after this year, providing I achieve the benchmark 60% requirement. I've been aiming much higher than 60% however as I REALLY want a first class honours qualification; I've...

Homework Statement A ball with a mass of 1220 kg is moving in a straight line heading due east when it collides elastically with a second ball that is at rest. After the collision the first ball deflects 27.9 degrees north of its original path and the second ball moves in a line 62.1 degrees...

Homework Statement A fixed mass of gas at a constant pressure of 1 x 105 N/m2 (pascal) expands to twice its volume at constant temperature of 27°C. The volume is then kept constant, and the gas is heated to 87°C. Calculate the final gas pressure. Homework Equations I think this is the...

Homework Statement Find the product of this http://www.webassign.net/ksorgchem2/14-P-019e1.jpg The Attempt at a Solution I tried this but it is wrong. http://www.webassign.net/marvinimages/e/d/b3dfb33e165ce17f7b0a8bab7b9d9d.png Not really sure what to do now.

Homework Statement What is the final temperature of water if 175 g steam at 150 C loses 423 KJ of energy? Homework Equations Q = M *C_p * Δ T Q = m * heat of (phase_change) The Attempt at a Solution This is how I would go about solving this problem. Going from steam to water requires...

Homework Statement The original problem is to solve u_t=u_xx+x with u(x,0)=0 and u(0,t)=0 by assuming there is a solution t^a*u(r), where r=x/t^b and a,b are constants Homework Equations The Attempt at a Solution This is a long problem, so I'm not writing everything. Following the...

Can help me with any idea what topic that suitable for 3 person in Mechanical Final Year Project? I am more with "design" and "built" mechanical parts.

Hello everyone this is my first post on PhysicsForums I am in my second year of electronic systems engineering degree and I have to choose a final year project. I am really enjoying the modules on RF engineering and electromagnetics, especially electromagnetics is just too interesting...

hello all! I am new to this forum. I am doing Mechanic of Solid ( summer course). I have come across with this problem , but I don't know how to solve it. I have attached the question. Could anyone help me? I don't know how to convert from density to force. in this questions given are...

Homework Statement Two metal balls of mass m1 = 2 g (diameter = 2 mm) and m2 = 6 g (diameter = 6 mm) have positive charges of q1 = 2 nC and q2 = 7 nC, respectively. A force holds them in place so that their centers are separated by 8 mm. What will their velocities be after the force is...

Hello all Friends, I am taking my undergraduate, majoring in Electrical Engineering, concentration in Control It takes 10 semester to pass, 1 semester=4months. Well it might be rare for you. And I am in 8th semester doing my internship as one of the criteria in the curriculum. In this...

I have a question. I'm conducting a drop test for packaging material and I need to find the pressure at the point of impact. What I did was drop a 18 lb ball 18". I converted the mass to 3.629g and the distance to 0.4572m to work in S.I. units then used the equation 2ad=Vf^2-V0^2. Afetr...

So i made up this simple setup: I have a √(2) meter stick slanted on a friction-less surface on a 45° angle. And i want to determine the final x and y positions of the points A and B. For point A: A.1) Solving for ax \sum F_x = T_x = F_xTcos(\theta) = ma_xa_x = \frac{Tcos(\theta)}{m} A.2)...

Homework Statement a small truck of mass 2.00*10^3 kg traveling at 72.0km/h experiences a force of 1.00*10^4 N for 0.800 s, when the brakes are applied. What is the final velocity? Homework Equations The Attempt at a Solution

Homework Statement I have been given this example with the following questions: 1. Two rocks are thrown off of a cliff with the same initial speed, v. The first rock is launched with at an angle Ө directed below the horizontal as shown below as 1, while the second rock is launched above at the...

Homework Statement A moving proton has 6.4x10^-16 J of kinetic energy. The proton is accelerated by a potential difference of 5000 V between parallel plates. http://members.shaw.ca/barry-barclay/Self-Tests/test09/elecst17.gif The proton emerges from the parallel plates with what...

Ask someone to pick 4 digits, but not all of them be the same. Zeroes are allowed as digits Form the largest number possible and the smallest number possible, including annexing any 0-digits to the left, Subtract the smaller number from the larger number, Write the difference as a...

I'm in high school and my english final was basically analyzing a short story and then writing an essay on what I thought the theme/message was. I completely and utterly screwed up, it was a really challenging piece but the conclusion I came to turned out to be completely wrong, and in hindsight...

Homework Statement A ball of mass 0.440 kg moving east (+x direction) with a speed of 3.30 m/s collides head on with a .220 kg ball at rest. If the collision is perfectly elastic what will be the speed and direction of each ball after the collision? Homework Equations...

Calorimetrey Problem -- Final Temperature of water Homework Statement In an insulated container, 0.50kg of water at 80C is mixed with 0.050kg of ice at -5.0C. After a while, all the ice melts, leaving only the water. Find the final temperature T_f of the water. The freezing point of water...

Homework Statement An adiabatically isolated system consists of 1 mol of a diatomic gas 100K and 2 mol of a solid at 200K separated by a rigid adiabatic wall. Find the equilibrium temperature of system after adiabatic wall is removed, assuming that the solid obeys the Dulong-Petit law...

Hi I am a final year student at Salford university manchester. I need idea for my final year project. Can anyone help me out n this matter Regards Sal

I needed to take a break from studying, and nobody was in PF chat to listen to my complaining! I need at least a 65 to keep an A. I don't know why I am so worried about it. Granted, I am out of practice on some of the earlier topics. Anyway, this course is sort of a milestone for me, because...

My physics teacher assigned a final paper and he wants us to write it using the guidelines that are used in the American Journal of Physics. Basically he wants the format of it. My topic is line integrals. But I have one problem. I can't find the format for submission online. I'm sick so I';m...

Homework Statement When two moles of CO are introduced into a vessel containing solid sulfur, the final equilibrium pressure is 1.03 atm. Determine Kp for the reaction: S(s) + 2CO(g) <--> SO2(g) + 2C(s) Homework Equations Kp=P(products)/P(reactants) Mole Fraction = mole of A/...

Hello, My background info: - Completed B.Sc in Math/Physics in april 2011 from a university in Canada. (GPA 2.8) - The first 2 years of study my grades weren't very good (1.8 to 2.3) and I was questioning what I wanted to do as a career the entire time. I ended up so far in I figured...

[b]1. The valve between a 5 liter tank in which the gas pressure is 911.925 kPa and a 10 liter tank containing gas at 4560 torr is turned open and equilibrium is established at constant temperature. What is the final pressure in the two tanks in atmospheres? [b]2. PV = nRT The...

Homework Statement So I had my final exam today in ODE and I had an equation which appeared to be exact, but was not. I also tried to find a special integrating factor to make it exact, but no success. I then attempted to manipulate it into a linear eq, tried separable variables, even...

Homework Statement 10.11g of CaO (molar mass = 56.08 g / mol) is dropped into a styrofoam coffee cup containing 157.0 g of H2O at 25.0ºC. If the following reaction occurs, calculate the final temperature of the water assuming that the cup acts as a perfect insulator. (Assume that the...

Homework Statement You throw a ball straight up @ 22m/s and you catch it 3.6 seconds later. How fast was it going when you caught it? Homework Equations v_f=v_i+at The Attempt at a Solution I found the right solution. But to me, it seems it should be more complex then this...

I solved the problem and have the correct answer just not sure about something. Question:What will be the equilibrium temperature when a 274 g block of copper at 317°C is placed in a 137 g aluminum calorimeter cup containing 829 g of water at 13.0°C? So heat lost by copper = heat gained...

One extremely hard question which someone has three hours to do. Would this a good final exam for a freshmen physics class? Would this be a good exam for any physics class?