Posts by Bruce
Total # Posts: 112
In the laboratory you will be provided with a 1.0 x 10-5 M primary stock solution of fluorescein (MW=332.31g/mol). The calibration curve should include a blank, 0.025, 0.05, 0.075, 0.10, 0.15, and 0.25 micromolar fluorescein solutions. Since you will be using 25 mL volumetric ...
October 18, 2016
maths literacy, economics, business studies, tourism, English, Afrikaans, L.O
I don't know what to study after grade 12 or where to study I don't have a career choices can someone please help me
January 28, 2016
In the figure, a thin uniform rod of mass m = 3.05 kg and length L = 1.11 m rotates freely about a horizontal axis A that is perpendicular to the rod and passes through a point at a distance d = 0.201 m from the end of the rod. The kinetic energy of the rod as it passes ...
July 25, 2015
You have 100 pieces of candy in five bowls. The sum of candy in bowl a and bowl b is 30 pieces. The sum of candy in bowl b and c is 36 pieces. The sum of candy in bowl c and bowl d is 49 pieces of candy. The sum of bowl d and bowl e is 47 pieces of candy. How many pieces of ...
February 1, 2015
The EPA requires hazardous waste incinerators to meet a standard of 99.99% destruction and removal of hazardous constituents injected into the incinerator. Determine the allowable quantity of contaminant in the exit stream if the incinerator is burning 1.0000 g/s of hazardous ...
January 15, 2014
You are tasked with preparing a 500mL nutrient solution containing 5mg/L of phosphorous (P), 3mg/L nitrate (NO3 -) and 100 mg/L chloride (Cl-). To make this solution, you have powdered sodium chloride, a 100 mg/L solution of phosphorus, a 1000 mg/L of sodium nitrate (NaNO3) ...
January 13, 2014
At time t =0, the current to the dc motor is reversed, resulting in an angular displacement of the motor shaft given by è = (198 rad/s)t (24 rad/s2)t2 (2 rad/s3)t3 (15 marks) a. At what time is the angular velocity of the motor shaft zero? b. Calculate the...
April 27, 2013
2. At time t =0, the current to the dc motor is reversed, resulting in an angular displacement of the motor shaft given by θ = (198 rad/s)t (24 rad/s2)t2 (2 rad/s3)t3 a. At what time is the angular velocity of the motor shaft zero? b. Calculate the angular ...
April 27, 2013
The electric field intensity at a point 2 meters from the surface of a uniformly charged conducting sphere is 1920 N/C. At a point 4 meters from its center, the electric field intensity is 3000 N/C. a.) Determine the radius of the sphere. Determine the electric field intensity...
February 4, 2013
There are two polarizing filters that are out of alignment by 30 degrees. If the light of intensity 1.00 W/m^2 and initially polarized half-way between the two filters passes through the two filters, what is the intensity of the transmitted light? I know the answer is 0.700 W/...
December 12, 2012
A fully charged 90-µF capacitor is discharged through a 60-Ω resistor. How long will it take for the capacitor to lose 80% of its initial energy? I know energy is given by E(t)=q(t)^2, but beyond that I really don't know how to solve this. Any suggestions are ...
October 24, 2012
A beam of X-rays with a wavelength Ü of 0.179nm is directed at an iron crystal whose planes have a spacing of 0.1013nm. How many diffraction peaks (each arising from a different order n) are possible? I'm really not sure how to go about solving this. Any help is...
September 19, 2012
The label on a soft drink states that 11 fl. oz (325 g) provides 285 kcal. The drink is cooled to 12.0°C before it is consumed. It then reaches body temperature of 37°C. Find the net energy content of the drink. (Hint: You can treat the soft drink as being identical to...
July 23, 2012
A uniform brass disk of radius R and mass M with a moment of inertia I about its cylindrical axis of symmetry is at a temperature T = 45 °C. Determine the fractional change in its moment of inertia if it is heated to a temperature of 125 °C. (The linear expansion ...
July 20, 2012
A sinusoidal wave traveling on a string is moving in the positive x-direction. The wave has a wavelength of 8 m, a frequency of 60 Hz, and an amplitude of 9 cm. What is the wave function for this wave? (Use any variable or symbol stated above as necessary.) I think the ...
July 17, 2012
A particular steel guitar string has mass per unit length of 1.79 g/m. and tension of 61.9 N. For the wave speed to be increased by 1.9%, how much should the tension be changed? I tried increasing the wave speed (186 m/s) by 1.9%, plug that into v=sqrt(T/linear mass density), ...
July 17, 2012
A mass m = 13 kg is connected to two different springs, one on the left and another on the right. It is displaced a distance x to the right from its equilibrium position. (Take k1 = 115 N/m and k2 = 198 N/m.) (a) What is the net force acting on the mass? (Use any variable or ...
July 13, 2012
The motion of a block-spring system is described by x(t) = A sin(ùt). Find ù, if the potential energy equals the kinetic energy at t = 6.11 s. I'm really not sure how to solve this. It seems that you need more information, either x or A? I appreciate any help...
July 13, 2012
A 3-kg mass attached to a spring with k = 130 N/m is oscillating in a vat of oil, which damps the oscillations. (a) If the damping constant of the oil is b = 19 kg/s, how long will it take the amplitude of the oscillations to decrease to 1% of its original value? (b) What ...
July 12, 2012
In reality you probably could, however it is not good science as it has been considered to be contamined or already used and a new substance or solution should be obtained. I know this is wasteful but, that is just how it is.
March 11, 2012
Calculate the amount of Na2HPO4*7H2O in grams needed to make 50 mL of a 0.40 M solution. I think this is dealing with molarity but i cant figure it all out for some reason? Help would be greatly appreciated.
March 11, 2012
The initial velocity of a 2.04 kg block sliding down a frictionless inclined plane is found to be 1.24 m/s. Then 1.23 s later, it has a velocity of 6.70 m/s. What is the angle of the plane with respect to the horizontal? im lost.....
January 30, 2012
An 88kg fisherman jumps from a dock into a 131kg rowboat at rest on the west side of the dock. If the velocity of the fisherman is 4.7m/s to the west as he leaves the dock, what is the final velocity of the fisherman and the boat. East is positive.
January 16, 2012
Calculate the pH of a solution created by mixing 200.0 mL of 0.400 M acetic acid and 200.0 mL of 1.00 M sodium acetate. Hint: The instant the two solutions are mixed what are the initial concentrations of each?
February 14, 2011
Billy has a bag of candy that contains 13 red pieces, 9 green pieces, 3 yellow pieces, and 7 orange pieces. If Billy reaches into the bag without looking, what color is he least likely to get?
January 9, 2011
. Margaret is planning to invest up to $22,000 in certificates of deposit at City Bank and Peoples Bank. She wants to invest at least $2,000 but no more than $14,000 at City Bank. Peoples Bank does not insure more than a $15,000 investment, so she...
December 2, 2010
A point is sliding along a curve y^2 = 1 + cos^3(2x) at whatever speed (even depending on time). Compute the ratio of the rates of change of the vertical and horizontal coordinate with respect to time when the point is at (x, y).
November 12, 2010
A 325.0-g piece of gold at 427°C is dropped into 200.0 g of water at 22.0°C. (The specific heat of gold is 0.131 J/g°C.) Calculate the final temperature of the mixture. (Assume no heat loss to the surroundings.) Can you please outline step by step how i would ...
October 22, 2010