Search results

  1. H

    Chemistry Classify each solid as a covalent, ionic, metallic, or molecular solid.

    1. Homework Statement As the title would lead you to believe I have to classify each solid as a covalent, ionic, metallic, or molecular solid. These are the given solids Calcium Fluoride Rhombic Sulfur Frozen Ethanol Pure Calcium 2. Homework Equations n / a 3. The...
  2. H

    Determine whether the series is convergent or divergent

    1. Homework Statement I have to find whether the following is Convergent or Divergent ∑ from n = 1 to infinity 2 / n(2n + 2)^(1/4) Actually it's the fourth root, this is just easier to write. 2. Homework Equations According to the front of the sheet it's a quiz on P-Series and Integral...
  3. H

    Computer Science Simple Animations

    1. Homework Statement Create a class called, ThreeObjectAnimation, that creates a graphic animation with three animation object. The ThreeObjectAnimation class should move three objects around the frame, either randomly, or following a fixed pattern. The movements should occur every 250...
  4. H

    Find the Current at a Certain Point

    1. Homework Statement For the circuit in the diagram below, R1 = 34.0 Ω, R2 = 20.0 Ω, ε1 = 8.50 V, ε2 = 10.5 V and ε3 = 10.5 V are connected as shown in the figure. What is the value of current I1...
  5. H

    Chemistry Calorimetry Question Find Final Temp.

    1. 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...
  6. H

    Magnetic Field in a Cylindrical Conductor

    1. Homework Statement A cylindrical conductor of radius R = 2.49 cm carries a current of I = 2.17 A along its length; this current is uniformly distributed throughout the cross-section of the conductor. Calculate the magnetic field midway along the radius of the wire (that is, at r = R/2)...
  7. H

    Using Boolean Algebra to Prove Equations

    1. Homework Statement There should be lines of some values to imply the "Not" form of them, however to make it easier, i'll just use the ¬ Symbol (a) Let x, y be elements of a Boolean algebra. Prove from the axioms that (x · y) + x = x. (b) Prove from the axioms of Boolean algebra that...
  8. H

    Magnitude of Electric Field from an Atom

    1. Homework Statement The neutral neptunium atom has 93 electrons. What is the magnitude of its electric field at a distance of 6.5x10-10 m from the nucleus? Hint: The number of protons in a nucleus is equal to the number of electrons in the neutral atom. q = 1.6e-19 * 93 =...
  9. H

    Electric Field Between two Charges Equals 0

    1. Homework Statement A 3.17 μC and a -2.19 μC charge are placed 3.65 cm apart. At what point along the line joining them is the electric field zero? Assume that the first charge is at the origin and the second charge is at +3.65 cm. 2. Homework Equations E = K(q) / r2 Ep = E1 + E2 0 =...
  10. H

    Finding the Net Charge of the Earth

    1. Homework Statement The Earth is surrounded by an electric field, pointing inward at every point. Assume a magnitude of E = 142N/C near the surface. a) What is the net charge on the Earth? b) How many excess electrons per square meter on the Earth's surface does this correspond to...
  11. H

    Resolution refutation help

    1. Homework Statement (a) Give a resolution refutation of the following formula: (x ∨ y) ∧ (y ∨ ¬z ∨ ¬x) ∧ ¬x ∧ (¬y ∨ x) (b) Convert the formula into CNF and give a resolution refutation for it: x1 ∧ (x1 ↔ x2) ∧ (x2 ↔ x3) ∧ (x3 →¬ x1) 2. Homework Equations n/a 3. The...
  12. H

    Simple Logic Question of Converting or to and

    Simple Logic Question of Converting "or" to "and" 1. Homework Statement As the title would have you believe it's really just a basic question. I have to write (¬q <---> r) /\ (¬p \/ ¬r) ---> (p \/ ¬q) just using "¬'s" and "/\'s" i know how to change everything else, but i cannot, for the life...
  13. H

    Deriving Basic Physic Problem Using Calculus

    1. Homework Statement At a distance of 45 meters from a traffic light, a car traveling 15 m/s is brought to a stop at a constant deceleration a) What is the value of Deceleration (-5m/s) b) How far has the car moved when its speed has been reduced to 3 m/s c) How many seconds would the...
  14. H

    Simplification of Logic

    1. Homework Statement Simplify the following compound statements (give a smallest formula equivalent to each of them). State which logical identities you used at each step (a) (p→q)↔(q→p) (b) ¬(p∧q)→(q→(p∨q)) 2. Homework Equations n/a 3. The Attempt at a Solution (a) ( p...
  15. H

    Damper Oscillator dropping amplitude to half the original value

    1. Homework Statement Consider a damped oscillator Assume that the mass is 318g, the spring constant is 104 N/m, and b = 0.106 kg/s. How long does it take for the amplitude to drop to half its initial value? M = 318 g Or 0.318 kg K = 104 N/m b = 0.106 kg/s 2. Homework Equations n / a...
  16. H

    Problems with probably very simple logic question

    1. Homework Statement The Island of Knights and Knave, where knights never lie; knaves lie always (that is, every statement made by a knight is rue, every statement made by a knave is false). a) Suppose you meet two islanders and ask who they are. One of them says "if i am a knight then so is...
  17. H

    Comp Sci Testing magic squares in Java

    1. Homework Statement Magic squares. An n × n matrix that is filled with the numbers 1, 2, 3, ..., n2 is a magic square if the sum of the elements in each row, in each column, and in the two diagonals is the same value. Write a program that reads in n2 values from the keyboard and tests...
  18. H

    Comp Sci Troubleshooting Array Lists in Java

    1. Homework Statement Input a list of n integer values into a 1-D array and do the following: • determine and output the number of positive values and the number of negative values • update the array values as follow • if the value is located at an even-numbered subscript, replace the value...
  19. H

    What is the largest area for $800

    1. Homework Statement a rectangular lot adjacent to a highway is to be enclosed by a fence. If fencing cost $6 per metre along the highway and $4 per metre on the other three sides, find the largest area that can be fenced off for $800. I get these questions generally, because they're...
  20. H

    Finding three Constants given only relative Max, and y intercept

    1. Homework Statement Find constants a, b, and c such that the graph of f(x) = ax2 + bx + c has a relative maximum at (5 , 12) and crosses the the y - axis at (0 , 3). 2. Homework Equations Not sure what to use 3. The Attempt at a Solution -- i don't have one --
  21. H

    Finding Values given only local max and min.

    1. Homework Statement Find the values of a and b if the function f(x) = 2x3 + ax2 + bx + 36 has a local maximum when x = −4 and a local minimum when x = 5. 2. Homework Equations I'm not even sure how to start this, it's just baffling me for some reason 3. The Attempt at a Solution...
  22. H

    Similar Triangles, Light and Shadow.

    1. Homework Statement A man 6 feet tall walks at a rate of 5 feet per second away from a light that is attached to a pole 15 feet above the ground. At what rate is the length of his shadow changing when he is 30 feet from the base of the pole? I get that this is really like a two similar...
  23. H

    Horizontal Tube Speed

    1. Homework Statement Seawater flows through a horizontal tube of diameter 3.00 cm that is joined to a second horizontal tube of diameter 1.70 cm. The pressure difference between the tubes is 7.25 kPa. What is the speed of flow in the first tube? 2. Homework Equations I thought it...
  24. H

    Some Clarification

    I apologize in advance for two things 1) If this is in the wrong section, and there's somewhere specific for Computer Science homework questions 2) how long this is going to be. I'm a first year comp-sci student, we just recently learned about if else, while, do-while, for stuff like that...
  25. H

    Finding Frequencies in Two Strings Stuck Together

    1. Homework Statement Two strings have different lengths (L1 = 3.920 m and L2 = 1.960 m) and linear densities (mL1 = 2.64E-1 kg/m and mL2 = 6.60E-2 kg/m), as the drawing below shows. |.........................................| |.........................................|...
  26. H

    How many Tangent lines go to a certain point.

    1. Homework Statement How many tangent lines to the curve y = x / (x + 1) pass through the point (1,2)? At which points do these tangent lines touch the curve? 2. Homework Equations n/a 3. The Attempt at a Solution I'm completely drawing a blank on this one. Help.
  27. H

    Finding Horizontal Tangents

    1. Homework Statement Find the points on the curve y=x3−x2−x+1 where the tangent is horizontal. I know that for it to be horizontal it needs a slope of 0 2. Homework Equations y = mx + b 3. The Attempt at a Solution I don't have one, i can't think where to even start with this.
  28. H

    Lowest Resonant Frequency Issues

    1. Homework Statement A 138 cm length of string has a mass of 4.98 g. It is stretched with a tension of 6.35 N between fixed supports. What is the wave speed for this string? What is the lowest resonant frequency of that wave? (wavelength) = 138cm = 1.38m M = 4.98g = 0.00498kg Ft =...
  29. H

    Earthquake distance to seismograph

    1. Homework Statement When an earthquake occurs, two types of sound waves are generated and travel through the earth. The primary, or P, wave has a speed of about 7.87 km/s and the secondary, or S, wave has a speed of about 4.86 km/s. A seismograph, located some distance away, records the...
  30. H

    Speed of a Wave (Literal Wave)

    1. Homework Statement A jetskier is moving at 8.30 m/s in the direction in which the waves on a lake are moving. Each time he passes over a crest, he feels a bump. The bumping frequency is 1.17 Hz, and the crests are separated by 5.30 m. What is the wave speed? Jetski's Speed = 8.30m/s...