Wednesday

April 1, 2015

April 1, 2015

Total # Posts: 42

**statistics**

The proportion of adults in the US with basic literary skills is 43%. If a hypothesis test is performed on this, how should you (in terms of the claim) interpret a decision that rejects the null hypothesis?
*June 13, 2012*

**Physics please help!**

Using the Bohr model, estimate the wavelength ë of the Ká characteristic X-ray for a metal an atom of which contains Z = 50 protons.
*April 22, 2012*

**Physics please help!**

Using the Bohr model, estimate the wavelength ë of the Ká characteristic X-ray for a metal an atom of which contains Z = 50 protons.
*April 21, 2012*

**Physics please help!**

An object is moving along a straight line and the uncertainty in its position is 1.1 m. (a) Find the minimum uncertainty in the momentum of the object. (b) Find the minimum uncertainty in the object's velocity, assuming that the object is a golf ball (mass = 0.045 kg). (c...
*April 21, 2012*

**Physics please help!**

A diffraction pattern forms when light passes through a single slit. The wavelength of the light is 680 nm. Determine the angle that locates the first dark fringe when the width of the slit is each of the following. (b) 1.20 x 10^-6 m
*April 15, 2012*

**physics**

A diffraction pattern forms when light passes through a single slit. The wavelength of the light is 680 nm. Determine the angle that locates the first dark fringe when the width of the slit is each of the following. (b) 1.20 10-6 m
*April 15, 2012*

**physics**

Two stars are 3.80 1011 m apart and are equally distant from the earth. A telescope has an objective lens with a diameter of 1.19 m and just detects these stars as separate objects. Assume that light of wavelength 550 nm is being observed. Also assume that diffraction effects...
*April 15, 2012*

**Physics please help!**

The far point of a nearsighted person is 5.8 m from her eyes, and she wears contacts that enable her to see distant objects clearly. A tree is 18.7 m away and 1.8 m high. (a) When she looks through the contacts at the tree, what is its image distance? (b) How high is the image...
*April 10, 2012*

**physics**

The far point of a nearsighted person is 5.8 m from her eyes, and she wears contacts that enable her to see distant objects clearly. A tree is 18.7 m away and 1.8 m high. (a) When she looks through the contacts at the tree, what is its image distance? (b) How high is the image...
*April 10, 2012*

**physics**

A converging lens (f = 12.6 cm) is held 8.55 cm in front of a newspaper, the print size of which has a height of 2.10 mm. (a) Find the image distance (in cm), (b) The height (in mm) of the magnified print.
*April 10, 2012*

**physics!**

The image produced by a concave mirror is located 27 cm in front of the mirror. The focal length of the mirror is 13 cm. How far in front of the mirror is the object located?
*April 2, 2012*

**physics!**

Light is incident from air onto the surface of a liquid. The angle of incidence is 50.7°, and the angle of refraction is 34.5°. At what angle of incidence would the reflected light be 100% polarized?
*April 2, 2012*

**physics please help!!**

A distant galaxy is simultaneously rotating and receding from the earth. As the drawing shows, the galactic center is receding from the earth at a relative speed of uG = 1.90 106 m/s. Relative to the center, the tangential speed is vT = 3.00 105 m/s for locations A and B, ...
*March 27, 2012*

**physics please help!!**

A distant galaxy is simultaneously rotating and receding from the earth. As the drawing shows, the galactic center is receding from the earth at a relative speed of uG = 1.90 106 m/s. Relative to the center, the tangential speed is vT = 3.00 105 m/s for locations A and B, ...
*March 27, 2012*

**physics **

Suppose that a police car on the highway is moving to the right at 26 m/s, while a speeder is coming up from almost directly behind at a speed of 37 m/s, both speeds being with respect to the ground. The police officer aims a radar gun at the speeder. Assume that the ...
*March 27, 2012*

**physics please help!!**

Suppose that a police car on the highway is moving to the right at 26 m/s, while a speeder is coming up from almost directly behind at a speed of 37 m/s, both speeds being with respect to the ground. The police officer aims a radar gun at the speeder. Assume that the ...
*March 26, 2012*

**Physics Help!!**

A 33.0-mH inductor has a reactance of 2.20 kΩ. (a) What is the frequency of the ac current that passes through the inductor? (b) What is the capacitance of a capacitor that has the same reactance at this frequency? (c) The frequency is tripled, so that the reactances of ...
*March 21, 2012*

**physics so confused**

1. A 26.0-Ω resistor, a 12.0-µF capacitor, and a 17.0-mH inductor are connected in series with a 150-V generator. (a) At what frequency is the current a maximum?
*March 21, 2012*

**physics please help!!**

Can you plug in the numbers for #1 please? I'm still a little confused.
*March 21, 2012*

**physics please help!!**

1. A 26.0-Ω resistor, a 12.0-µF capacitor, and a 17.0-mH inductor are connected in series with a 150-V generator. (a) At what frequency is the current a maximum? 2.A series circuit contains only a resistor and an inductor. The voltage V of the generator is fixed. If...
*March 21, 2012*

**physics**

A 33.0-mH inductor has a reactance of 2.20 kΩ. (a) What is the frequency of the ac current that passes through the inductor? (b) What is the capacitance of a capacitor that has the same reactance at this frequency? (c) The frequency is tripled, so that the reactances of ...
*March 21, 2012*

**physics**

A 33.0-mH inductor has a reactance of 2.20 kΩ. (a) What is the frequency of the ac current that passes through the inductor? (b) What is the capacitance of a capacitor that has the same reactance at this frequency? (c) The frequency is tripled, so that the reactances of ...
*March 21, 2012*

**physics**

In a series circuit, a generator (1254 Hz, 13.8 V) is connected to a 15.5-Ω resistor, a 4.25-µF capacitor, and a 5.32-mH inductor. Find the voltage across each circuit element. VR = VC = VL =
*March 20, 2012*

**physics**

A series circuit contains only a resistor and an inductor. The voltage V of the generator is fixed. If R = 20 Ω and L = 2.8 mH, find the frequency at which the current is one-fifth its value at zero frequency?
*March 20, 2012*

**science**

Danny sails a boat downstream. The wind pushes the boat along at 21 km/hr. The current runs downstream at 15 km/hr. What is the actual velocity of the boat
*February 7, 2012*

**physics**

Suerat made paintings in which separate dots of color are placed close together on the canvas, and from a distance they merge in the eye to form an image. Consider such a painting with the dots in the painting separated by 1.7 mm and assume that the wavelength of the light is...
*February 3, 2010*

**Physics**

In a single-slit diffraction pattern on a flat screen, the central bright fringe in 1.0 cm wide when the slit width is 4.70 10-5 m. When the slit is replaced by a second slit, the wavelength of the light and the distance to the screen remaining unchanged, the central bright ...
*February 3, 2010*

**Physics**

A tow truck is pulling a car out of a ditch by means of a steel cable that is 10.2 m long and has a radius of 0.50 cm. When the car just begins to move, the tension in the cable is 870 N. How much has the cable stretched? COnstant for Steel cable Y=2.0e11
*November 21, 2009*

**physics**

A bungee jumper, whose mass is 87 kg, jumps from a tall platform. After reaching his lowest point, he continues to oscillate up and down, reaching the low point two more times in 8.5 s. Ignoring air resistance and assuming that the bungee cord is an ideal spring, determine its...
*November 15, 2009*

**biological science**

cant move cant reproduce do not react to heat, cold ect do not participate in excretion
*November 15, 2009*

**English**

Grandma said yes, we need more apple juice. Correct for capitalization and punctuation.
*February 18, 2008*

**physics word problem**

why are lightweight tires preferred over lightweight frams in bicycle racing?
*October 17, 2007*

**physics problem**

why are lightweight tires preferred over lightweight frams in bicycle racing?
*October 16, 2007*

**physics**

why are lightweight tires preferred over lightweight frams in bicycle racing?
*October 16, 2007*

**AP CHEM!**

IM SO CONFUSED PLEASE HELP! H2 +CO2-->H2O + CO When H2 is mixed with CO2 at 2,000K, equilibrium is achieved according to the equation above. In one experiment, the following equilibrium concentrations were measured. [H2]= 0.20mol/L [CO2]= 0.30mol/L [H2O]=[CO]= 0.55mol/L a/ ...
*April 3, 2007*

**precal!**

Prove: (3cosx + 4sinx)^2 + (4cosx - 3sinx)^2=5 ...this is all under the square root sign. I get 9cos^2x + 16sin^2x +16cos^2x + 9sin^2x now i know that sin^2 equals 1-cos^2....so would that be 9cos^2x + 17-cos^2x+16cos^2+ 10cos^2x? if not please help..and if this is correct.....
*March 28, 2007*

**trig**

express this in sinx (1/ cscx + cotx )+ (1/cscx- cotx) i got 2sinx is that right?? and B) express in cosx problem: is 1 + cotx/cscx - sin^2x i get to the step of 1 + cos-sin^2x and im stuck..help! (1/cscx + cotx) + (1/cscx - cotx) = (sinx + cosx/sinx) + (sinx - cosx/sinx) = ...
*March 28, 2007*

**calculus**

express in sinx 1 1 ---------- + -------- cscx + cotx cscx - cotx and express in cosx 1 + cot x ------- - sin^2x cscx = 1/sinx so what do i do w. that extra one on the top!?? im so confused cscx Your fractions aren't lining up. This question is also not calculus. Please do...
*March 27, 2007*

**factoring cubes**

how to factor x^3-27 well since 27 is a perfect cube and so is x^3 wouldn't the answer be x-3? no, its something like (2x-3)(?x^2+?X+?) i dont know how to figure all the parts out. Here's the format for the difference between two cubes: (a - b)(a^2 + ba + b^2) = a^3 - ...
*January 18, 2007*

**Calculus**

find derivitive of 1/square root of x 1/square root of x = x^(-1/2) The derivative is -1/2 x^(-3/2) can you keep going on the problem to not have negative exponents? You can also use that the derivative of 1/f(x) is given by: -f'(x)/[f(x)]^2 If you take f(x) = sqrt(x) and ...
*January 18, 2007*

**math**

e^(-X/2)=12 do i bring the (-x/2) down by ln? how do i procede after that? thanks e^(-x/2) = 12 (-x/2) = ln12 -x = ln12 * 2 x = -(ln12 * 2) can you a also help me with this one? x^2ln(x)=ln(x) thanks x^2 = ln(x)/ln(x) x^2 = 1 x = +/-1
*October 25, 2006*

**Math**

calculus help needed example: sin-1(-1/2) how do you figure this out? The sin^-1 means the arcSin, or the angle whose sine is ... so sin^-1(1/2) is the angle whose sine is -.5, which is -30 degrees. In your calculator, put in -.5, then press INV sin. so as my answer do i put ...
*October 25, 2006*

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