No idea Definition and 88 Threads

  1. D

    Motivated, but have no idea where to start

    Hi, I am not a math person. I am terrible at math and have made it to college feeling like I have missed out on something great. Not only have I made it to college, but I am what liberal arts students consider "retired from math". I have completed the math credit I need to fulfill my major...
  2. Z

    What Was Your Original Speed on the Freeway?

    Homework Statement Driving along a crowded freeway, you notice that it takes a time t to go from one mile marker to the next. When you increase your speed by 7.0 mi/h, the time to go one mile decreases by 12 s. What was your original speed? Homework Equations D = VT The Attempt at a...
  3. P

    Sound wave no idea how to do it

    Homework Statement (a) A thin, taut string tied at both ends and oscillating in its third harmonic has its shape described by the equation y(x,t) = 5.60cm (sin[(0.0340 rad/cm)x]sin[(50.0 rad/s)t]), where the origin is at the left end of the string, the x-axis is along the string and the...
  4. L

    Formation Reaction Problems: No Idea how to solve it

    Write formation reactions at 1 atmosphere pressure and 25°C for each of the following substnaces: Mercury (I) chloride solid Nitroethane (CH3CH2NO2) liquid I have absolutely no idea how to do this. If anyone can help show or explain to me how to solve this, I'd appreciate it
  5. N

    I have no idea how to do (very very basic) proofs help guide me?

    Homework Statement Let A and B be any sets. 1: Prove A is the disjoint union of A\B and A intersect B. 2: Prove A U B is the disjoint union of A\B, A intersect B, and B\A. Homework Equations ? The Attempt at a Solution I understand most of the basic terminology used. I know disjoint...
  6. T

    Circular motion I HAVE NO IDEA WHAT I AM DOING

    Homework Statement A ball of mass M attached to a string of length L moves in a circle in a vertical plane as shown (picture of circle with a radius drawn L and M as a ball on the circle.) the tension at the top in the string is twice the weight of the ball. At the bottom the ball JUST clears...
  7. J

    Physics Homework Question due in 20mins, literally have no idea what i'm doing

    014 (part 1 of 2) 10.0 points A(n) 19 g object moving to the right at 24 cm/s overtakes and collides elastically with a 34 g object moving in the same direction at 14 cm/s. Find the velocity of the slower object after the collision. Answer in units of cm/s. 015 (part 2 of 2)...
  8. J

    Physics Homework Question due in 20mins, literally have no idea what i'm doing

    Homework Statement A(n) 71.3 kg person throws a(n) 0.047 kg snowball forward with a ground speed of 45 m/s. A second person, of mass 64.7 kg, catches the snowball. Both people are on skates. The first person is initially moving forward with a speed of 2.28 m/s, and the second person is...
  9. B

    Help i hav no idea how to work out the design load

    help i hav no idea how to work out the design load! Homework Statement A typical floor layout of a reinforced concrete office building is shown in Figure 5. The reinforced concrete floor supports a permanent dead load G (ceiling services, floor finish and partitions, but not self-weight) of...
  10. I

    Circular motion problem no idea what's going wrong ><

    Homework Statement A highway curve of radius 560m is designed for traffic moving at a speed of 73.0km/hr (1216m/s). What is the correct banking angle of the road? Homework Equations a=v^2/r F=ma The Attempt at a Solution Forces in t direction: Fnet=Fncos\vartheta-Fg=0...
  11. A

    Rat of reaction problems i have no idea how to do

    A certin chemical reaction is carried out at 45C and the rate observed is 280M/s. What will the rate of the reaction be at 55C? i have no idea what equation to use for this problem could someone break it down for me step by step
  12. X

    What are some suitable topics for a paper about physics?

    Hello, I need to write a paper about physics and I hvae no idea at all what I could write about. Just about a topic related to physics. Could be based on an article, a book, video etc. I was going to write about an interesting article about physics , but I can't find anything :frown...
  13. C

    Finding Values of k for 6k2+4k in the Form 6ab+5a+b?

    can somebody please tell me if there is any way to find all values of k for which 6k2+4k is of form 6ab+5a+b? eg. for k=1, 6k2+4k=10=6x0x2+5x2+0
  14. W

    Half Life / Alpha Decay Question - No IDea

    Half Life / Alpha Decay Question -- No IDea Homework Statement A space rock contains 3.20 g of 147 62 Sm and 0.110 g of 143 60 Nd. 147 62 Sm alpha decays to 143 60 Nd with a half-life of 1.06 1011 yr. If the rock originally contained no , how old is it? Homework Equations ...
  15. S

    Least Squares Regression Analysis - No Idea

    Hello, I am a first year undergraduate university student majoring in Engineering and Computing Sc. One of my courses is Linear Algebra. We have been given an assignment in which question no. 2 is out of syllabus. It is on Least Squares Regression Analysis. This has not been taught to us. We...
  16. T

    No idea how to start this tension/cable problem

    I'm having a really hard time figuring out where to start this problem, let alone finish it. Can anyone help me through it? I attached a scanned picture of the problem. Thanks, Matt
  17. A

    I'm really having a problem integrating this equation, infact i have no idea

    Homework Statement Please tell me how to integrate this... Homework Equations [(2x + 4)][(2x^2 + 3x + 1)^(1/2)] The Attempt at a Solution
  18. T

    I have no idea where to start with this plane mirror question

    Homework Statement does anyone know how to do this plane mirror question? The rear window in a car is approximately a rectangle, 1.29 m wide and 0.330 m high. The inside rear-view mirror is 0.480 m from the driver's eyes, and 1.27 m from the rear window. What is the minimum height of the...
  19. G

    Easy problem, but no idea how to solve it?

    Homework Statement A motorbike with the velocity 40km/h is able to stop at a distance, D, when it brakes with maximal deacceleration. At what distance will a car with a velocity of 60 km/h stop? Homework Equations . The Attempt at a Solution I was trying to solve it through regular...
  20. D

    What could be causing the discrepancy in Y0 when finding the placement vector?

    given the acceleration Ax=6t^2 Ay=-0.66PI*cos(0.66PI*t) and knowing that the starting point was (0,0) and that the starting velocity was V0=(-1,0) find the Velocity vector and the placement vector si what i did was- 1st integral on Ax Ay getting Vx= 2t^3-1 Vy=-sin(0.666PI*t) which...
  21. R

    Volume of Ellipse No idea how to do this

    Homework Statement Rotating the ellipse x^2/a^2 + y^2/b^2 = 1 about the x-axis generates and ellipsoid. Compute its volume. Homework Equations The Attempt at a Solution
  22. Saladsamurai

    What is the breakdown of electric power sources in Salem, MA?

    Homework Statement So I am supposed to write up a report as part of one of those "design" problems in a Thermo text. I am supposed to find determine the respective contributions to the electric power provided to customers by the electric utility serving my area (Salem,Ma) attributable to...
  23. T

    No idea how to find the equation of a plane

    would this be ok for this question because i thought we had to find normals and things and every site i go on about plane equations is different and i need to know this for an exam tomorrow. find the equation of a plane that passes through the points (2,-2,1)(4,-1,6)(3,-3,-2) (1)2a-2b+c=d...
  24. P

    Desperatly , have no idea where to start

    Homework Statement A block of 10kg is on a plane elevated 35 degrees. if it starts at rest at the bottom of the 10m ramp, and the coefficient of kinetic friction is .15, what is the force need to push the block up the entire ramp in 8.0s. Homework Equations The Attempt at a...
  25. E

    Absolutely no idea how to solve these

    I'm asking you guys for serious help in these homework for Engineering physics. 1) Protons having a kinetic energy of 5.00 Me are moving in the positive x direction and enter a magnetic field B = 0.050k (T) directed out of the plane of the page and extending from x=0 to x=1.0 m . Calculate...
  26. D

    Linearization - no idea how to do this

    Can someone point me in the right direction for this problem. I have no idea how to start on this. I know the linearization formula but i don't know if that's what i have to use here. can someone please help problem: You want a linearization that will replace the function over an interval...
  27. K

    What Is the Problem with the Electron's Travel Distance in the Field?

    Anybody body know how to do this problem or have an idea what the problem is about. See attached for diagram and question. I would like to understand and possible solve the problem if anyone can help. https://www.physicsforums.com/attachment.php?attachmentid=7406&stc=1&d=1154053940...
  28. T

    How Can Jane Calculate the Minimum Time to Climb the Vine?

    Hello, i have another question, sorry i didn't post them together. But I'm stuck again ... and this time i have no idea how to solve... Question: Jane wishes to quicky scale a slender vine to vist Tarzan in his treetop hut. The wine is known to safely support the combined wieght of Tarzan...
  29. P

    I have no idea how to start this help

    A stuntman whose mass is 70 kg swings from the end of a 4.0-m-long rope along the arc of a vertical circle. Assuming he starts from rest when the rope is horizontal, find the tensions on the rope that are required to make him follow his circular path,(a) at the beginning of his motion, (b) at a...
  30. L

    How do i get to solve this integral,i have no idea whatsoever so no

    how do i get to solve this integral,i have no idea whatsoever so no one should expect what i have done.it was presented to me by a colleague [x^(1/x)]^[x^(1/x)]^[x^(1/x)]^[x^(1/x)]^[x^(1/x)]^[x^(1/x)]^[x^(1/x)]...
  31. S

    How Does Transforming to Moving Coordinates Simplify a Hyperbolic PDE?

    define L[u] = a \frac{\partial^2u}{\partial t^2} + B \frac{\partial^2 u}{\partial x \partial t} + C \frac{\partial^2u}{\partial x^2} = 0 Show that if L[u] is hyperbolic and A is not zero, the transofrmation to moving coordinates x' = x- \frac{B}{2A} t t' =t takes L into a mutliple...
  32. O

    A question and no idea what to do

    determine the inital velocity of a projectile that is luncked horizantaly and falls 1.5m while moving 16m horizantaly i tried everything all i figerd out is that they r displacmednts the accelaration is 9.8 and nothing i don't have enogh info to do anything please help me
  33. P

    Help With Problem Setup: No Idea What the Hint Says

    I have no idea what the hint tells me to do...please help me set the problem up...
  34. recon

    Proving No Positive Integer Solutions for 1/x^2 + 1/xy + 1/y^2 = 1

    Prove that there are no positive integers x & y such that \frac{1}{x^2} + \frac{1}{xy} + \frac{1}{y^2} = 1 . I really have no idea where to start. I tried rearranging the equation, but I could not see anything useful in any of the rearrangements.
  35. J

    I have no idea how to integrate by parts

    I don't think anyone in class understands it, we went over it so quick. The only thing I seem to get is that uv - (integral) vdu = (integral) udv. You are supposed to assign u, v, dv and du, but how do you know which is u and which is v? What is the difference between du and dv? Are you...
  36. B

    Rotational Motion. Apparently, I have no idea what I'm doing.

    ok... We were given the following question... (I apologize for it's length... please bear with me) A thin long cylindrical rod (mass M radius R and length l) is initially rotating about its long axis with angular momentum L. There are no external forces or torques however interestingly Ke is...
  37. M

    Help whit a problem. (I have no idea)

    Calculate e^A if A = \left(\begin{array}{cc}0 & -2\\1 & 3\end{array}\right) Maybe using that e^x = \sum_{n=0}^\infty \frac{x^n}{n!} , then e^A = \sum_{n=0}^\infty \frac{\left(\begin{array}{cc}0 & -2\\1 & 3\end{array}\right)^n}{n!} but i don't know if this is the right way for...
  38. S

    Kissing Electric Shocks, No Idea Whats Causing It

    I just don't get it, I've noticed that over the last three days when my girlfriend and I kiss we both get a nasty electric shock, and a crack sound can be heard, its driving us crazy, I've tried wearing differnt clothes, differnt shoes, having a shower and bath, touching metal objects, nothing...
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