Minimum Definition and 1000 Threads

  1. F

    Arithmetic mean and geometric mean

    If a, b, and c are positive real numbers and a² + b² + c² = 3, what is the minimum value of the expression [1/(1+ab)] + [1/(1+bc)] + [1+(1+ac )]? Usage: A² + B² + C² ≥ AB+AC+BC Answer: 3/2
  2. F

    I Gradient descent algorithm and optimizers

    Hello, To find the minimum (global or local) of a function, we can set the function's gradient equal to zero and solve for the $x$. This is the classic, analytic approach to find the minimum and it works if the function is differentiable and if it has not to many parameters (how many?) An...
  3. R

    Show that the minimum in alpha-decay spectrum is caused by interference of peak

    This problem set considers (beta-delayed) alpha decay of ##{}^{20}Na##. I'm currently stuck in the following exercise and was hoping some of you could help me in the right way. Thanks in advance! The problem is: c) The experimental spectrum of ##{}^{20}Na## can be found below. Apart from peaks...
  4. N

    Engineering Minimum Hamming Distance for Parity Check Matrix

    My answer: Then, if I am not mistaken, the solution made in that video is mostly guessing about which columns combination can be equals to zero and I found 1st, 2nd, and 3rd rows as well as 2nd, 3rd, 4th rows are equals to zero so the minimum hamming distance is 3 since my answer is mostly...
  5. R

    Where in orbit should a rocket fire to escape with minimum ΔV

    I am really lost on how to deal with this. Since this is an elliptic orbit, the mechanical energy is negative. For the rocket to escape orbit, we have to get the mechanical energy to be equal to or greater than zero. I thought at first that it would escape in the perigee, since that's where the...
  6. B

    I Checking if a stationary point is a minimum using Lagrangian Mechanics

    I'm having trouble understanding how to find out whether or not a stationary point is a minimum and I'm hoping for some clarification. In my class, we were shown that, using Euler's equation, the straight-line path: with constants a and b results in a stationary point of the integral: A...
  7. A

    I Why is the minimum energy equal to the energy uncertainty?

    I was watching this video on Youtube, however, I don't get the step at 14:50 where he says that ΔE≥½hf means that E0=½hf. Could someone explain why the minimum energy is equal to the energy uncertainty?
  8. J

    I Minimum light bulb wattage for solar simulator

    I am trying to design a simple homemade PV solar simulator. I have picked metal-halide lamps as my light source. If the PV panel has an area of 1m^2 and I wanted to achieve spatial uniformity across the irradiated surface with an irradiance of 1000 W/m^2, how do I go about selecting what...
  9. A

    Calculate the minimum force required

    I tried taking the components but got stuck there on what value of theta I should take
  10. crememars

    Evaluating minimum and maximum values with calculations

    Hi! I know this may seem like a silly question but I really just want to make sure I understand this correctly. I've already calculated the minimum and maximum values for time and height: t min = 0.58 s t max = 0.68 s y min = 1.98 m y max = 2.02 m To calculate the minimum average speed, would...
  11. S

    How to find minimum possible mass

    Unfortunately, this is not the right answer.
  12. P

    Minimum screw thread engagement to support weight?

    Hello All, I know there are rules of thumb and thread engagement calculators online but I am trying to find mathematically what the minimum number of threads acceptable would be. I currently have an eyebolt that will be torqued to a specific value. This eyebolt setup will then need to lift a...
  13. D

    Minimum Length of Cuts for Unfolding Box Into Flat Sheet?

    Hi everyone I got 36 cm as the answer for the following problem, but it's supposed to be 32cm. These are the cuts I have 4 x 5cm = 20cm 2 x 3cm = 6 cm 1 x 10cm = 10cm which adds up to 36cm. I can get 32cm with 4x3=12 2x5=10 1x10=10 But I don't think that would be the correct net. Is...
  14. DavidBalut

    I The Theoretical Minimum: Length Contraction and Time Dilation

    Hello, My name is Dave and I'm a physics major at UIUC. It looks like I will be taking the special relativity course (phys 225) this fall. I've always been fascinated by the theory so I decided to get a head start with Lenny and Art's perspective on it. My first head-scratching moment came in...
  15. Simobartz

    I Request for an example of minimum energy principle (thermodynamics)

    Summary: Request for an example of minimum energy principle usage The minimum energy principle states that, for a system at constant entropy, volume and other extensive quantities, the internal energy is minimized at equilibrium. Can you give me an example in which, using this principle, is it...
  16. S

    MHB Minimum of product of 2 functions

    Hello Simple question Whether the minimum of the product of two functions in one single variable, is it greater or less than the product of their minimum thanks Sarrah
  17. K

    I Postulating a minimum gravitational field strength

    this paper postulating a minimum gravitational field strength postulating a minimum gravitational field strength (minimum curvature) and a minimum acceleration but otherwise leaving Gr could reproduce MOND [Submitted on 25 May 2022] MONG: An extension to galaxy...
  18. LCSphysicist

    How Does Quantum Uncertainty Define the Position of a Positron?

    So, let's assumed ##v_i = (v_i \pm \Delta v_i)##. We can say that, for minimum values, $$\Delta X_i \Delta v_i = \hbar / (2m)$$. $$\Delta X_i = \frac{\hbar}{2 m \Delta v_i} \implies V_{min} = \Delta X \Delta Y \Delta Z = \frac{\hbar}{2 \Delta v_x m } \frac{\hbar}{2 \Delta v_y m} \frac{\hbar}{2...
  19. rudransh verma

    What is the minimum force needed to move a block with friction present?

    We know the minimum force to move the body in presence of friction will be ##F>\mu F_N## But it’s not right.
  20. physicks885

    Minimum seperation of two electrons moving toward each other

    [Mentor Note -- Two threads started by partners in a class have been merged into this one thread, since they are working on a shared solution to turn in]
  21. S

    Find the minimum perimeter of a triangle with these constraints

    My attempt: $$|\vec{BA} -\lambda \vec {BC}| \geq 2|\vec {BC}|$$ $$|\vec {BA}|^2 -2 \lambda (\vec {BA} \cdot \vec {BC}) +\lambda ^{2} |\vec {BC}|^2 \geq 4|\vec {BC}|^2$$ $$|\vec {BA}|^2 -2 \lambda |\vec {BA}| \cos \theta +\lambda ^{2} \geq 4$$ Am I even on the right track? Thanks
  22. shivajikobardan

    MHB What is minimum requirement vs specific requirements to be called in as intelligent agent for any software code piece?

    https://uobrep.openrepository.com/bitstream/handle/10547/223815/ESWA%20agent%20paper%20-v2.pdf;jsessionid=16B243A8F6C1FC1242A75969D18D00B7?sequence=5 here is some information but i am unable to dcode what is minimum requirement vs specific requirements. can you help me a bit in this case?
  23. S

    Quantum 'Quantum mechanics the theoretical minimum' book

    I want to know about the book 'quantum mechanics: the theoretical minimum' book by Leonard Susskind. Is it a book worth buying
  24. S

    How to find the angle where the required pull is minimum?

    Can I get some help on how I'd do that? I would parametrize the angle in the equation of where T = 188N and then take the derivative. And then, what should I do then? it's not T' = 0 and I didn't have maxima minima vals in calc so yeah. Thanks in advance.
  25. JD_PM

    How to determine the minimum grid length | Numerical Plasma Physics

    Summary:: I am learning particle-in-cell (PIC) python 3X code. PIC currently represents one of the most important plasma simulation tools. It is particularly suited to the study of kinetic or non-Maxwellian effects. I am learning particle-in-cell (PIC) python code. PIC currently represents one...
  26. MisterH

    A Minimum sample length to estimate the frequency of a sinusoid

    Given a discretely sampled horizontal sinusoid of length p, and unknown amplitude, what is the minimal number of consecutive points on a window that is required to correctly estimate its total length, starting at any random point on the wave? Initially I would think it would be either p (full...
  27. M

    MHB Optimization - Lagrange multipliers : minimum cost/maximum production

    Hey! :giggle: Business operates on the basis of the production function $Q=25\cdot K^{1/3}\cdot L^{2/3}$ (where $L$ = units of work and $K$ = units of capital). If the prices of inputs $K$ and $L$ are respectively $3$ euros and $6$ euros per unit, then find : a) the optimal combination of...
  28. Istiak

    Find the values of A, B, and C such that the action is a minimum

    > A particle is subjected to the potential V (x) = −F x, where F is a constant. The particle travels from x = 0 to x = a in a time interval t0 . Assume the motion of the particle can be expressed in the form ##x(t) = A + B t + C t^2## . Find the values of A, B, and C such that the action is a...
  29. S

    Minimum Frequency of FM Data / Catastrophic Error Scenario?

    Ever since I learned about FM something's been bugging me, which is that the PLL error correction acts on the encoded data, seeming to leave open the possibility of the shape of the data itself interfering with the PLL's interpretation of what the carrier frequency is. It seems dangerous to mix...
  30. bob012345

    Is Wastewater Recycling the Solution to Extreme Drought?

    Due to the extreme drought, what is the minimum amount of water required to wash a small car such as a Corolla and how would you do it?
  31. M

    MHB F doesn't have in (0,0) a local minimum

    Hey! :giggle: We have the function $\displaystyle{f(x,y)=y^2-3x^2y+2x^4}$ and the function $\displaystyle{g_v(t)=f(tv_1, tv_2)=t^2v_2^2-3t^3v_1^2v_2+2t^4v_1^4}$. I have shown that $g$ has a local minimumat $t=0$ I want to show that $f$ has not a local minimum in $(0,0)$. The gradient is...
  32. M

    MHB Points of the surface with minimum distance to the point (3,0,0)

    Hey! :giggle: We have the function $$f(x,y)=(x-3)^2+y^2+(x-y)^2$$ and I have shown that at $(2,1)$ we have a minimum and so $f(2,1)\leq f(x,y)$ for all $(x,y\in \mathbb{R}^2$. I did that in this way: I calculated the gradient and set this equal to zero and found that the only critical point...
  33. N

    MHB Which procedure takes the minimum time to solve modulus functions?

    1) -|2x-3|+|5-x|+|x-10|=|3-x| 2) |2x-3|-|5-x|-|x-10|-|3-x|=28 3) -|2x-3|+|5-x|+|x-10|≥|3-x| How can we solve these problems? The method I know is to plug in the critical values to see which modulus becomes positive and which one becomes negative. Then find out the values of x for which the...
  34. Hamiltonian

    Medical Minimum amount of sleep per night for 4 months

    I am a 17 year old male with no major health conditions. I want to know if there will be any long term effects of less sleep(and practically no sleep schedule) ranging from anywhere between 4-5 hours a night(sprinkled with occasional all-nighters) for a period of 4-5 months. a quick google...
  35. M

    Minimum Tone Spacing: Coherent Frequency Shift Keying

    Hi, I was reading through some online notes and was wondering: when dealing with coherent FSK, what is the minimum tone spacing and why? I know that for non-coherent FSK, we can show that the minimum is: ## f_1 - f_0 = \frac{1}{T} ## where ## T ## is the symbol period. However, if we are now...
  36. khodournajem

    Minimum motor power for a mechanical horizontal sieving machine

    r = 2.5 l=10 cm angle = 0 (maximum connecting rode elongation) w = 0.5 (30 rpm) n=10/2.5 = 4 so the acceleration is 1.5×0.5×0.5(1 + 1/4 ) = 0.4 m/s friction force = 10*9.81*0.3 = 29.4 Newton. Crank force is the mass of the object into acceleration. So crank force = 10 × 0.4 = 4 Newton...
  37. L

    MHB Prove the minimum and maximum edges in a graph

    Hello! I am having trouble solving the right part of the inequality. For left part of the inequality $n-k \le m$, here’s how I did it Let $ n = v_{1} + v_{2} + v_{3}...+v_{k}$, the sum of vertices of each component in G least number of edges = $(v_{1}-1) + (v_{2}-1) + (v_{3}-1)...+(v_{k}-1)$...
  38. C

    RF Transistors, is there a 'minimum' frequency where they work?

    Some RF transistors are not 'characterised' for lower frequencies, can they still be used? I get that a lower operating frequency (HF/1.8MHz) may not be the commercial target for an UHF transistor (>136MHz) so no effort spent on characterising them. Likewise HF transistors >1.8MHz not...
  39. I

    Minimum length x for no slipping

    I'm letting the weight of the hanger be W. Since there is no slipping, the total frictional force will be = total weight. When the load of 50W is placed at X, there'll be a normal force at the left end of the pole on top to the left, and another normal force at the right end of the pole at the...
  40. anemone

    MHB Finding the Minimum $x$ for a Prime Product

    Find the minimum value for $x$ where $x\in \mathbb{N} $ and $x^2-x+11$ can be written as a product of 4 primes, which are not necessarily distinct.
  41. PhysicsTest

    Minimum voltage supplied to motor windings

    I have seen the following specifications in the Hurst motor data sheet. i have confusion on the Minimum DC voltage to the motor windings. It says as 10Vdc, but even if i give less than 10V it should not damage the motor windings. I can understand the upper voltage if i cross it may damage the...
  42. V

    Using an ODE to show a local minimum

    The ODE given to us is y' = xcosy. I am having a bit of trouble when it comes to solving this problem. We are supposed to show that the solution has a local minimum at x = 0 with the hint to think of the first derivative test. However, I am only really familiar with the first derivative test...
  43. F

    Minimum energy of a photon to produce ##\pi^+##

    I have a doubt about the first request: I suppose to find the minimum energy of ##\gamma## in the situation where ##p## is stationary, there is no reason to say that the proton is stationary if I were to calculate it in the CM, right?. So I have to consider che LAB-frame to find ##E_\gamma##...
  44. J

    Minimum or Maximum value of a multivariate function

    First thank you for taking your time to take a look at this simple question. And sorry for the informal math language and equations, I hope you guys can understand it. So, depending on the case, I have 2 or 8 simple quadratic functions f(a), f(b), f(c),… f(z). Each a,b,c,…,z have a different...
  45. richengle

    What is the minimum gyroscope speed to yield force precession?

    Does anyone know what the minimum speed of a gyro to make it so a force at 0deg will yield a movement at 90deg... or even better, what the angle is wrt speed... see http://www.copters.com/aero/gyro.html for pictures. -thx, rich
  46. M

    MHB Find path to minimum cost from start to finish

    Hey! 😊 I am looking the following: The board of a game is an $M \times N$ board with squares, where the starting point is on left - in position $(0, 0)$ - and the finish is in the lower right - in position $(M-1, N-1)$. Each square contains a positive number that describes the cost of moving...
  47. Monoxdifly

    MHB What Is the Minimum Surface Area for a Cuboid Box with a Square Base?

    The volume of a cuboid box with a square base is 2 litres. The production cost per unit of its top and its bottom is twice the production cost per unit of its lateral sides. Suppose the side length of its base is x and the height of the cuboid is h. The minimum production cost is reached when...
  48. Monoxdifly

    MHB What is the Minimum Length of AP + PB?

    The point A is located on the coordinate (0, 5) and B is located on (10, 0). Point P(x, 0) is located on the line segment OB with O(0, 0). The coordinate of P so that the length AP + PB minimum is ... A. (3, 0) B. (3 1/4, 0) C. (3 3/4, 0) D. (4 1/2, 0) E. (5, 0) What I did: f(x) = AP + PB...
  49. anemone

    MHB Min Value of $a^2+b^2$ in Quadratic Equation

    Determine the minimum value of $a^2+b^2$ when $(a,\,b)$ traverses all the pairs of real numbers for which the equation $x^4+ax^3+bx^2+ax+1=0$ has at least one real root.
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