Homework — 398 discussions

  1. bluesteels

    Exam Prep: Electric Field - Is It Zero?

    I'm having an exam soon so i want to make sure. Is the electric field here zero?? cause if i draw gauss surface covering both of them they should cancel out or am i wrong.
  2. A

    Engineering Building an isosceles triangle in plane engineering drawing

    Hello, i wasn't in enginnering drawing class since 2 weeks because i was sick and my high school teacher told me to do this homework. This is what I've done so far I did not build the triangle 'cause i am not sure. Please, i just want that someone accompanies me with steps by steps explanation...
  3. Robin288

    Electrostatics homework problem help

    Summary:: I been stuck on this problem from past 4 months. I am completely done. I am getting no idea. Even my professor couldn't have helped me. Can anyone please help me? 😔
  4. A

    Tools for writing physics solutions with equations and screensharing

    Greetings! I'm a 4th year physics undergrad looking for a program/tablet that I can write/type equations into and type (or dictate!) sentences into for clarification. I have Word but the equation editor is clunky. I also tutor so being able to screenshare a large area in Zoom and easily...
  5. E

    High School Can waste-to-energy produce more energy than needed to vaporize the waste?

    Burning waste in a waste-to-energy plat, can more energy be produced by burning the trash then the amount of energy needed to heat the trash to the point it vaporises? (to turn it to ash) eg we have 100 J of energy inside some rubbish, and this energy would all be released when we incinerate the...
  6. Franklie001

    AC circuit analysis involving resistors and inductors

    Summary:: Hi anyone can explain me how to solve this circuit, finding the current I2 and I1? Really don't know where to start Thanks
  7. S

    Homework help : What object rotates at 90 RPM?

    H
  8. Darsh_22

    How do I sketch a flow profile and solve for curl in vector calculus?

    Hello, Can someone explain how to sketch the flow profile in detail. Also, I solved for curl, but I'm getting a zero while the answer is the differentiation of the function f(y). Pls do help me out!
  9. M

    How can I solve these induction and function problems in my French homework?

    I would really appreciate if someone helped me do this homework, btw it's in french
  10. sigurdfromnor

    (Movement Homework) What is the speed of a marble falling on the moon?

    Sorry for the bad english. This might sound stupid but I am pretty new the physics and i can't seem to find what formula to use on this problem when only the mass, gravity and height of the fall is given. and i can't find a similar problem in the book, could someone give me any pointers? Thanks...
  11. Camden

    Year 10 physics homework problem

    I got this as homework and I am not sure how to attempt it
  12. R

    Electric field and potential at midpoint between two charged spheres

    Hello, any answers appreciated: 'Two spheres are 5 m apart. Sphere 1 has a charge of -20 mC and sphere two has a charge of -50 mC. (a) Find the strength of the electric field at the sphere's halfway point. (b) Find the electric potential at the halfway point
  13. N

    Compensating for Earth's Rotation With v = ωr

    We know that ##v = \omega r## where ##r = R_{\text{E}} + h##. To compensate for the motion, the plane must fly along the equator at the same speed as the Earth but in the opposite direction, i.e. from east to west, so $$\vec{v} = -\vec{ v}_{\text{E}}$$ $$v_{\text{E}} = \omega_{\text{E}}...
  14. Ineedhelpwithphysics

    Why does a stretched object have more inertia?

    I have no clue. The answer is the stretched one but i don't know why.
  15. L

    Proving the conjugate of a complex fraction property

    I need help actually creating the proof. I've done the scratch needed for the problem, it's just forming the proof that I need help in. Bar(a+bi/c+di)= (a-bi) / (c-di) Bar ((a+bi/c+di)*(c-di/c-di)) = ((a-bi/c-di)*(c+di/c+di)) Bar((ac+bd/c^2 +d^2)+(i(bc-ad)/c^2+d^2)) =...
  16. mncyapntsi

    Intro Physics homework help - distance and velocity

    I have tried this problem over 4 times and keep getting the exact same answer, which is incorrect. Could someone please help by pointing out what I did wrong, or letting me know if I am actually on the completely wrong path? Thanks! Have a wonderful day :)
  17. E

    Engineering Finding air density or velocity for water cooled air cooler

    I'm not looking for someone to tell me the answer, just help steer me in the right direction. I feel like I need to find the air density or air velocity at entry to proceed, but I'm unsure any help and guidance is greatly apricated!
  18. This Is Me

    How Is Ampere's Law Applied to Calculate Magnetic Fields?

    (I accidentally missed my lesson and I don't know how to apply this question to the formula)
  19. O

    What Formula Do I Need for This Optics Problem?

    Unfortunately, there's no formula i know about, so i have no idea how to solve this... Hope you can help me out... Greetings
  20. Y

    What does the dot mean in JM² = KM · LM?

    Summary:: Tripped by my grand daughter's math homework again! This is the homework of my grand daughter, I don't understand the question: I wrote the questions in red. I have not done geometry for a long time! I don't understand the equation JM^2 = KM . LM. Is the "dot" just multiply? or is...
  21. leminn

    Binding energy per nucleon of the nucleus

    How exactly would it then be calculated? Here's what I have tried: proton mass: 1.007276 amu Neutron mass: 1.008665 amu Sulphur-34 mass: 33.9678668 amu Calculation: 1.##(16\cdot1.007276)+(18\cdot1.008665)+(16 \cdot0.000549)=34.28117## 2.##34.28117-33.9678668=0.3133032## 3. 1 atomic mass...
  22. P

    Can a transformer problem have two correct answers for coil ratios?

    Answer B would increase the n1/n2 ratio and increase the deflection. Making it correct. But also, Answer A would increase the current through the primary coil, and hence the power. This would increase the power in the secondary coil hence I2, leading to lower voltage V2. Making it also correct...
  23. N

    Graduate Mapping circular bevel gear profiles to conical surfaces

    The paper is https://core.ac.uk/display/10365043 (12MB pdf) My purpose is to construct parametised spiral bevel gears (using OpenSCAD). I know how to produce a correctly formed circular cut (cylindrical) crown gear profile. My problem is mapping that to a conical surface. I am looking for...
  24. J

    Identifying wavelength from standing wave diagram with fractional positions

    Points A b AND C are shown in first diagram Im confused about question three... I feel like its related to wave length but the fractions are throwing me off.
  25. Pipsqueakalchemist

    Engineering Centripetal motion and angular acceleration in rotating rod

    For this problem I know how to get the answers but I have a few things I’m not 100% sure about. First how do we know that the rod is experiencing centripetal motion? Second, when using moment about point G how do we know that the angular acceleration is equal to zero? And third the radius is 0.4...
  26. Pipsqueakalchemist

    Engineering Dynamics homework — Does this cabinet sliding on the floor tip over?

    So for this question, when using point B as the centre of the moment, I get different sign for the mad term. If you take clockwise as positive than 100N force and the force at point G are causing a positive moment and gravity is causing an negative moment. But the solutions have different signs...
  27. Pipsqueakalchemist

    Engineering Why do contact points between gears have equal speeds?

    So I’m confused about a few things in the solution. Why is it that speed of the V_h appears on both gear a and b? Is it because both gears are both in contact so they have equal speeds just in opposite direction. Same confusion for V_e being on the top of gear b. So Just because gear e doesn’t...
  28. S

    Engineering Norton's theorem circuit giving 4V instead of 2V

    So I've just learned Norton's Theorem and I have this problem on my homework assignment that is wrong. I've checked the answer with a circuit simulator(PSPICE) and the simulation said that V0 should be a drop of 2V. However, my simplified circuit shows a voltage drop of 4V. I have been staring...
  29. T

    Relating potential difference and electric field

    I tried following the formula but it wasn’t correct. I’m sure I could get it if I had an example as I’m sure this must be a simple question for other people I was just unsure if I was doing it correct.
  30. petha1

    Why does a star 15 minutes behind the sun not appear at night?

    March 21 - October 21 = 7 months. So the star is only 15m 39,3 seconds behind the sun. This means that the star won't be up when the sun is down. Answer: No, the star will set only 15 minutes after the sun has set. Therefore it won't be on the sky at the specified latitude during dark hours...
  31. petha1

    Calculating Mars mass from Phobos orbit and stellar cooling time

    1. Keplers third law (and the asumption that M1+M2 ~ M1) gives that M_Mars = 4*Pi^2*a^3/(G*T^2) With numerical values inserted Mmars = 4*3.14^2*(9400*1000+3396.97*1000)^3/((6.67*10^-11*(7*60*60+39*60)^2) 2. Phobos needs 7h39 minutes to complete a circle, this gives a speed of...
  32. N

    Why is sinusoidal wave equation a standing wave?

    ψ(y,t)= -2A sinky sin wt Why is this called a standing wave?
  33. O

    Finding individual marble mass from group measurements

    I arranged the masses in ascending order: 11.0 g 11.1 g 20.6 g 21.4 g 21.5 g 25.7 g 25.8 g 25.9 g 31.6 g 31.9 g I found the average mass of the marbles: 22.65 g I found the difference in masses of the marbles: 0.1 g 9.5 g 0.8 g 0.1 g 4.2 g 0.1 g 0.1 g 5.7 g 0.3 g I found the average of the...
  34. O

    Finding spring compression and velocity on a trampoline using energy conservation

    For a) I did Eg = Ee + Eg and tried to solve for x. I got 5.4 m but I think this is wrong. I have no idea how to do the rest, please help :')
  35. L

    Projectile motion: finding time when object reaches specific height

    Hey, I am new to this community and I am in need of help with this physics problem. I have used the formula above and the answer I get is 1.43s. The correct two answers are 0.68s and 2.4s. For the Vf the answer is 8.3 m/s.
  36. A

    How Should Compass Bearings Be Notated in Navigation Problems?

    150 km tan(35)=150/x Hyp=316.58 I know this isn't right where did I go wrong or did I even start correctly
  37. T

    Average Kinetic Energy of molecules calculation

    the answer in the solution book is 29K which only comes if I use mass for only one atom. ( They did not show any working ) My attempt: 1/2 x (1.67 x 10^(-27)) x (355)^(2) = 3/2 x 1.38 x 10^(-23) x T T = 29.48820652 K The confusion arises when I tried the following question: Q. Estimate the...
  38. C

    Determine the force in the bar CB

    I solved this with two methods as you can see down below in the picture. Which is the correct way? I remember I learned in class you could use both ways but why am I getting different results?
  39. A

    Experiment using an Ostwald Viscometer

    Summary:: Not sure how to My question is what is h2o , because ts is for example : 48,25 and what is ps . Is h20 the 0,99708? 48,25
  40. OscarF

    Terminal velocity of a falling object with air resistance

    Below I've attached the question - I don't know why this question is so difficult, perhaps I missed a lesson or such, however I've Benn working at it for ages and got nowhere...
  41. yecko

    Partial derivative of h/T with respect to temperature

    From the solution of my thermodynamics homework, $$ ({\frac{\partial h_{fg}/T}{\partial T}})_P \\ = ({\frac{\partial h_{g}/T}{\partial T}})_P - ({\frac{\partial h_{f}/T}{\partial T}})_P = \frac{1}{T} ({\frac{\partial h_{g}}{\partial T}})_P - \frac {h_g}{T^2} - \frac{1}{T} ({\frac{\partial...
  42. jackplaysgames

    Finding weight on another planet using gravitational equations

    For question A, I know that I am supposed to input the numbers given into the Universal Gravitation Equation, but I do not know how to solve for it beyond that. For question B, I know that the astronauts weight depends on the mass and gravity of the new planet but I do not know how to prove it...
  43. B

    Work done accelerating a 1500 kg car from 11 m/s to 25 m/s

    Homework Equations Conservation of energy. Kinetic energy=(1/2)mv^2 The Attempt at a solution m=1.5*10^3kg, final velocity=25m/s, initial velocity= 11m/s, distance=0.20 and work done=? What do I do next.
  44. M

    How Do You Formulate and Solve Rational Inequalities?

    My attempt so far: I put all the terms to become smaller than zero: so ##x<-4## becomes ##x-4<0## ##-1\leq x\leq 3## becomes ##-1-x\leq 0## and ##x-3 \leq 0## ##x>6## becomes ##x-6>0## which is the same as ##-x+6<0## (i think)... I am now stuck on making it a rational inequality... anyone...
  45. A

    A bouncing ball hits a blob of putty on the rebound upward

    Please someone help me
  46. T

    Work done by three forces on an object sliding horizontally

    Here's a diagram of the object My Question: My friend and I were solving this problem. We both found Fxnet and Fynet. However to find work I did W= Fnet*d whereas he did W= Fxnet* d. He claims that since it's sliding on the floor it can only go in the x-direction, and it can't go in the...
  47. C

    What velocity does the particle need to get to point B?

    It was a long time ago I did these kind of problems so I’m a bit rusty. The only thing I can think of is divide it up to two parts one x and one y. In y the acceleration is sin(a)*9.82? Then put that in the equation and solve for t. In x the there is no acceleration so the formula is x=V0*t, I...
  48. C

    How far can the person climb up the ladder before it starts sliding?

    Look on picture two for my equations, I’m pretty sure my first three equations are correct as it’s the same on the answer paper I got. Answer paper only shows the three equations and correct answer so I have no idea how they got to it. When I put the equations togheter And solve out ”h” i get...
  49. C

    What is the resulting force between the beam CB and E?

    I assumed that the vertical force at point B would be the same as the force between beam CB and E because of Newtons law. Did I assume wrong? Look below for my calculations and answer which I got to 250N. I don’t know the correct answer but assume someone here can tell me if I solved the problem...
  50. M

    Engineering Finding coefficient of viscosity in ball falling through fluid experiment

    Edit: So I have written out equation 3 again and taken a picture to show my working out, the 2 things that I am confused about is how do I find the coefficient of viscosity? I know that syrup is high viscosity and water is low viscosity but I don't know the equation to get the actual value. The...