Wednesday

January 18, 2017
Total # Posts: 398

**Physics**

Zinc has a work function of 4.30 ev . A 4.50eV photon strikes the surface and an electron is emitted. What is the maximum possible speed of the electron?

*November 28, 2011*

**Physics**

A spherical virus has a diameter of 50mm . It is contained inside a long, narrow cell of length . What uncertainty does this imply for the velocity of the virus along the length of the cell? Assume the virus has a density equal to that of water.

*November 27, 2011*

**Physics**

The speed of an electron is known to be between 3.0×10^6 m/s and 3.3×10^6 m/s . Estimate the uncertainty in its position.

*November 27, 2011*

**physics**

The speed of an electron is known to be between 3.0×10^6 m/s and 3.3×10^6 m/s . Estimate the uncertainty in its position.

*November 26, 2011*

**algebra**

brad wants to buy flowers for his friend with 27 $ . the daises are $1 each and the roses are $3 each. he buys 3 more daises then roses. how much did the roses cost?

*November 22, 2011*

**Physics**

Problem 17.11 Light from a helium-neon laser (wavelenght = 633 nm) is used to illuminate two narrow slits. The interference pattern is observed on a screen 3.0 m behind the slits. Thirteen bright fringes are seen, spanning a distance of 52 mm . Part A - What is the spacing (...

*November 9, 2011*

**Physics**

Problem 17.8 Light from a sodium lamp (wavelenght = 598) illuminates two narrow slits. The fringe spacing on a screen 150cm behind the slits is 4.0 mm . Part A - What is the spacing (in mm ) between the two slits? Express your answer using two significant figures.

*November 9, 2011*

**Chemistry**

1 c 2 a 3 d 4 b

*November 9, 2011*

**physics**

Problem 17.8 Light from a sodium lamp (wavelength = 598) illuminates two narrow slits. The fringe spacing on a screen 150 cm behind the slits is 4.0 mm . Part A - What is the spacing (in mm ) between the two slits? Express your answer using two significant figures.

*November 8, 2011*

**Physics**

Problem 17.8 Light from a sodium lamp (wavelenght = 589) illuminates two narrow slits. The fringe spacing on a screen 150 cm behind the slits is 4.0 mm . Part A - What is the spacing (in mm ) between the two slits? Express your answer using two significant figures.

*November 7, 2011*

**Physics**

Problem 17.8 Light from a sodium lamp (wavelenght = 589) illuminates two narrow slits. The fringe spacing on a screen 150 cm behind the slits is 4.0 mm . Part A - What is the spacing (in mm ) between the two slits? Express your answer using two significant figures.

*November 7, 2011*

**Physics**

Problem 17.8 Light from a sodium lamp (wavelenght = 589) illuminates two narrow slits. The fringe spacing on a screen 150 cm behind the slits is 4.0 mm . Part A - What is the spacing (in mm ) between the two slits? Express your answer using two significant figures.

*November 7, 2011*

**Physics**

Problem 17.26 A thin film of (MgF2) n= 1.38 coats a piece of glass. Constructive interference is observed for the reflection of light with wavelengths of 500nm and 625nm . Part A - What is the thinnest film for which this can occur?

*November 6, 2011*

**Physics**

Problem 19.33 Two light bulbs are 1.0 m apart. Part A - From what distance can these light bulbs be marginally resolved by a small telescope with a 3.0cm -diameter objective lens? Assume that the lens is limited only by diffraction and wavelenght = 600nm . Express your answer...

*November 5, 2011*

**Physics**

Problem 17.6 A helium-neon laser beam has a wavelength in air of 633nm . It takes 1.48 ns for the light to travel through 31.0 cm of an unknown liquid. Part A - What is the wavelength of the laser beam in the liquid? Express your answer with the appropriate units.

*October 26, 2011*

**Physics**

Problem 17.6 A helium-neon laser beam has a wavelength in air of 633nm . It takes 1.48 ns for the light to travel through 31.0 cm of an unknown liquid. Part A - What is the wavelength of the laser beam in the liquid? Express your answer with the appropriate units.

*October 26, 2011*

**physics**

How long does it take light to travel through a 3.2mm -thick piece of window glass?

*October 23, 2011*

**algebra**

A street vendor sells about 20 shirts each day when she charges $8 per shirt. If she decreases the price by $2, she sells about 10 more shirtseach day. How can she maximize daily revenue?

*October 23, 2011*

**physics**

Problem 25.52 A 100-turn, 2.0-cm-diameter coil is at rest in a horizontal plane. A uniform magnetic field 60 degrees away from vertical increases from 0.50 T to 1.50 T in 0.60 s . Part A What is the induced emf in the coil? Express your answer using two significant figures.

*October 10, 2011*

**physics**

Problem 25.52 A 100-turn, 2.0-cm-diameter coil is at rest in a horizontal plane. A uniform magnetic field 60 degrees away from vertical increases from 0.50 T to 1.50 T in 0.60 Part A What is the induced emf in the coil? Express your answer using two significant figures.

*October 9, 2011*

**physics**

Problem 25.52 A 100-turn, 2.0-cm-diameter coil is at rest in a horizontal plane. A uniform magnetic field 60 degrees away from vertical increases from 0.50 T to 1.50 T in 0.60 Part A What is the induced emf in the coil? Express your answer using two significant figures.

*October 9, 2011*

**physics**

Problem 25.52 A 100-turn, 2.0-cm-diameter coil is at rest in a horizontal plane. A uniform magnetic field 60 degrees away from vertical increases from 0.50 T to 1.50 T in 0.60 Part A What is the induced emf in the coil? Express your answer using two significant figures.

*October 9, 2011*

**physics**

Problem 25.49 A 1.40-m-diameter MRI solenoid with a length of 2.80 m has a magnetic field of 2.50 T along its axis. Part A - If the current is turned off in a time of 1.2 s, what is the emf in one turn of the solenoid's windings? Express your answer using two significant ...

*October 9, 2011*

**math**

1500-1800

*October 5, 2011*

**physics**

A mass spectrometer is designed to separate protein fragments. The fragments are ionized by removing a single electron and then enter a 0.80 T uniform magnetic field at a speed of 2.3 * 10^5 m/s. If a fragment has a mass that is 85 times the mass of the proton, what will be ...

*October 1, 2011*

**Math**

i have no idea

*September 28, 2011*

**Physics**

Problem 22.2 2 *10 ^13 electrons flow through a transistor in 1.0 ms. Part A - What is the current through the transistor? Express your answer using two significant figures.

*September 27, 2011*

**Chemistry**

how to you calculate the partition coefficient of benzoic acid .13 grams in a 1.6 mL CH2Cl2 and 1.6 mL water?

*September 26, 2011*

**Physics**

Problem 22.2 2*10^ 13 electrons flow through a transistor in 1.0 ms. Part A - What is the current through the transistor? Express your answer using two significant figures. in mA

*September 25, 2011*

**Physics**

Problem 22.2 2*10^ 13 electrons flow through a transistor in 1.0 ms. Part A - What is the current through the transistor? Express your answer using two significant figures. in mA

*September 25, 2011*

**chemistry**

how to you find the partition coefficient of the benzoic acid in CH2Cl2 in water

*September 25, 2011*

**Physics**

Problem 22.16 A 7.5 v battery supplies a 3.5 mA current to a circuit for 8.2 Hr . Part A - How much charge has been transferred from the negative to the positive terminal? Express your answer using two significant figures. Part B - How much work has been done on the charges ...

*September 25, 2011*

**physics**

would the current be 2*10^13 X -1.6*10^-19 divided by 1?

*September 25, 2011*

**physics**

Problem 22.2 2 *10^13 electrons flow through a transistor in 1.0ms . Part A - What is the current through the transistor? Express your answer using two significant figures. in mA

*September 25, 2011*

**physics**

Problem 21.10 A proton with an initial speed of 800000 m/s is brought to rest by an electric field. Part B - What was the potential difference that stopped the proton? = Part C - What was the initial kinetic energy of the proton, in electron volts?

*September 14, 2011*

**Physics**

Problem 21.40 A pair of 10uF capacitors in a high-power laser are charged to 1.7kV. Paige Nieuwenhuis Part A - What charge is stored in each capacitor? Express your answer using two significant figures. Part B - How much energy is stored in each capacitor? Express your answer...

*September 13, 2011*

**Physics**

Problem 21.79 The plates of a 3.2 nF parallel-plate capacitor are each 0.25 m^2 in area. Part A - How far apart are the plates if there's air between them? Express your answer using two significant figures. Part B - If the plates are separated by a Teflon sheet, how thick...

*September 13, 2011*

**Physics**

A parallel-plate capacitor consists of two square plates 18 Cm on a side, spaced 0.50 mm apart with only air between them. What is the maximum energy that can be stored by the capacitor?

*September 12, 2011*

**Physics**

Problem 21.79 The plates of a 3.2nF parallel-plate capacitor are each 0.25 m^2 in area. Part A - How far apart are the plates if there's air between them? Express your answer using two significant figures. = Part B - If the plates are separated by a Teflon sheet, how thick...

*September 11, 2011*

**Physics**

Problem 21.10 A proton with an initial speed of 800000 m/s2 is brought to rest by an electric field. Part B - What was the potential difference that stopped the proton? Part C - What was the initial kinetic energy of the proton, in electron volts?

*September 9, 2011*

**algebra 1**

How do I simplify and justify the steps to: (4+105x)+5

*September 6, 2011*

**Physics**

Item 10 Two equally charged, 1.00 spheres are placed with 2.00 between their centers. When released, each begins to accelerate at 225 m/s2 Part A - What is the magnitude of the charge on each sphere? =

*September 1, 2011*

**physics**

Item 9 A small glass bead has been charged to 20 Part A - What is the magnitude of the acceleration of a proton that is 4.0 from the center of the bead? Express your answer using two significant figures. = Part B - What is the direction of the acceleration of a proton that is...

*August 29, 2011*

**physics**

Item 4 Two 2.0 masses are 1.0 apart on a frictionless table. Each has 1.0 of charge. Part A - What is the magnitude of the electric force on one of the masses? Express your answer using two significant figures. = Try Again; 3 attempts remaining Part B - What is the initial ...

*August 29, 2011*

**physics**

A small plastic sphere with a charge of -5.0 is near another small plastic sphere with a charge of -15 . Part A - If the spheres repel one another with a force of magnitude 8.3×10−4 , what is the distance between the spheres? Express your answer using two ...

*August 28, 2011*

**Physics**

Item 4 Two 2.0 masses are 1.0 apart on a frictionless table. Each has 1.0 of charge Part A - What is the magnitude of the electric force on one of the masses? Express your answer using two significant figures. = Part B - What is the initial acceleration of each mass if they ...

*August 28, 2011*

**Physics**

Part A - What is the magnitude of the electric force on charge in the figure?

*August 28, 2011*

**Literacy 2**

English paper is MLA and a Psychology paper is APA

*August 23, 2011*

**CHEM 102**

Can someone help me with this question please? What is the pH at each of the points in the titration of 25.00 mL of 0.1000 MHCl by 0.1000 M NaOH:i) After adding 25.00 mL NaOH ii) After adding 26.00 mL NaOH thankyou

*August 18, 2011*

**Geometry**

Find d in the the simplest radical form. Right square pyramid with equilateral triangular faces. The base and sides are 8 and d is in the middle of the pyramid with a dotted line down the middle. I am just really confused on the formula to use for this problem. I would ...

*June 23, 2011*

**Physiology**

Which structures of the inner ear would be activated by a somersault? A cartwheel? By fast acceleration in a race car?

*June 2, 2011*

**math**

how do you figure out the length, width and height of a box with a volume of 570 cm3 and a surface area of 478 cm2.

*May 15, 2011*

**math**

how do you figure out the length, width and height of a box with a volume of 570 cm3 and a surface area of 478 cm2.

*May 15, 2011*

**Physics Class**

A crowbar is used to wrench open a wooden crate. The crowbar is situated so that a point 8 cm from the end digging into the box acts as a pivot point. The crobar is gripped on the other side, 29 cm away from the pivot. If the person exerts a force of 110 lbs on the crobar, how...

*April 28, 2011*

**Physics Class**

A 965 kg car is driving along a boardwalk. The car's center of mass is 45 cm in front of the rear wheels, and the distance between the front and rear wheels is 2 m. What total force does the car's front tires exert on the boardwalk? Give your answer in Newtons.

*April 28, 2011*

**Physics Class**

The equation describing the motion of an object is y=0.8cos(4.2t+0.32). What is its period?

*April 28, 2011*

**Physics Class**

A 166 g mass is attached to a horizontally mounted spring. It is pulled out to stretch the spring and then released. You determine the period of the oscilliation to be 1.0 seconds. What is the acceleration of the mass (magnitude) when the spring is stretched 33 cm during the ...

*April 27, 2011*

**Physics/Math**

The equation describing the motion of an object is y=0.8cos(4.2t+0.32). What is its period? I don't know how to figure this out?

*April 27, 2011*

**Physics**

A 166 g mass is attached to a horizontally mounted spring. It is pulled out to stretch the spring and then released. You determine the period of the oscilliation to be 1.0 seconds. What is the acceleration of the mass (magnitude) when the spring is stretched 33 cm during the ...

*April 26, 2011*

**physics**

A 65 g meter stick has two masses, each 250 g placed upon it. The first is located at 72 cm and the second located at 41 cm. Where should you place your finger if you wished to balance the meter stick? Give your answer in cm.

*April 25, 2011*

**Physics**

A 984 kg car is driving along a boardwalk. The car's center of mass is 33 cm in front of the rear wheels, and the distance between the front and rear wheels is 2 m. What total force does the car's front tires exert on the boardwalk? Give your answer in Newtons.

*April 24, 2011*

**Biology**

I believe that I have answered the following questions correctly, but would like some reassurance. organisms that are used to decontaminate soils may a. store contaminates in their tissues b. release pollutants into the air c. degrade the pollutants d. be plants or ...

*April 22, 2011*

**Calc 2**

Aha I got it! Thanks so much! :)

*April 18, 2011*

**Calc 2**

Mggraph: but (r*cos(theta))^2 is not x^2, is it? I thought rcos(theta) = x^2 This is what I got: 1 = 5y/[(x^2)(square root of(x^2 + y^2))]

*April 18, 2011*

**Calc 2**

I am sorry, it is r = 5tan(theta)sec(theta)

*April 18, 2011*

**Calc 2**

Find a Cartesian equation for the polar curve y = 5tan(theta)sec(theta). I think I got it but I just wanted to double check. Thanks in advance!

*April 18, 2011*

**Physics**

You are riding a bicycle at a speed of 15 m/s. The bycicle has tires with diameters measuring 630 mm. You can approximate each tire as a solid cyllinder (to calculate inertia) with a mass of 0.5 kg. What is the total rotational kinetic energy of the bicycle?

*April 8, 2011*

**Physics**

i sill don't get it?

*April 8, 2011*

**Physics**

When throwing a ball, a pitcher exerts a torque of 150 N m for 0.15 seconds onto their arm before letting go of the ball. With an arm length of 0.9 m with inertia 0.6 kg m2, what is the speed of the ball just after it is released?

*April 8, 2011*

**PHysics**

The tip of a helicoptor rotor blade can reach speeds of roughly 300 mph (130 m/s). It takes about 30 seconds to get them up to speed and they have a typical radius of 20 feet (6 m). What is the average angular acceleration of the rotor blades as they get up to speed?

*April 6, 2011*

**Math**

29 tapes

*March 30, 2011*

**Math**

When you join Sally's Video Club, there is no rental charge for the first 2 tapes. Each tape then costs $2 to rent, but you can borrow one tape free as a bonus after renting 10 tapes. How many tapes would you be able to rent for $50?

*March 30, 2011*

**math**

What are 10 numbers that have a median of 21, a range of 20, and a mode of 10?

*March 24, 2011*

**Physics**

Two objects are mocing about so that their total momentum is zero. What can be said about their kinetic energy? Choose the most descriptive answer. a. the kinetic energy must be greater than zero b. the kinetic energy must be negative c. the kinetic energy must be equal to or ...

*March 21, 2011*

**Physics**

You are trying to package a 50g egg so that it won't break after you drop it from a height of 10 meters. You decide to use wood as a nice soft packaging to protect the egg. When the egg hits the ground, the wood "softens" the landing so that it takes 5 ...

*March 21, 2011*

**Physics**

Two objects are moving about so that their total momentum is zero. What can be said about their kinetic energy?

*March 21, 2011*

**Physics**

The game is called Ice Bocci. You play by sliding pucks across the ice into each other, sort of like marbles. One player slides the red puck straight into a stationary green puck. The red puck is sliding with a speed of 4 m/s and weighs twice as much as the green puck. What ...

*March 20, 2011*

**Physics**

You design a roller coaster that has an initial drop from some height "h" followed by a loop and then the ride comes to a stop. If the loop of a circle with a diameter of 50 m, what is the minimum height you would need to make sure nobody falls out? (Ignore friction)

*March 4, 2011*

**Algebra 2 word problem**

just checking to see if i have this problem correct Sammy can cut wood twice as fast as Joe. When they both work together, it takes them 4 hrs. how long would it take them to do the job alone? 4/x +4/x+2 = x^2+2 4x+4x+8= x^2+2 8x+8= x^2+2 x^2-6x-8=0 (x-4)(x+2) x=4 x=-2 since i...

*March 2, 2011*

**checking to see if this is right**

just checking to see if i have this problem correct Sammy can cut wood twice as fast as Joe. When they both work together, it takes them 4 hrs. how long would it take them to do the job alone? 4/x +4/x+2 = x^2+2 4x+4x+8= x^2+2 8x+8= x^2+2 x^2-6x-8=0 (x-4)(x+2) x=4 x=-2 since i...

*March 2, 2011*

**Algebra 2 word problem**

Just wanted to check to see if these are correct. Thank you, Please check if a greyhound bus travels 7mph slower than the express bus. the express bus travels 45 miles in the time it takes the greyhound bus to travel 38 miles. find the speed of each bus greyhound 38/x-7 ...

*March 2, 2011*

**biology**

what forms between the other two primary tissue layers

*March 1, 2011*

**Algebra 2**

Just checking to see if I got this right. Thanks, (3x^4--8x^2 -3x-3) / (x^2-3) 3x^2+1 remainder -3x

*March 1, 2011*

**Organic Chemistry**

what is the major product if 2,3,3-trimethylpentane was mixed with IBr?

*March 1, 2011*

**Algebra 2**

Just checking to see if I got this right. Thanks, (3x^4--8x^2 -3x-3) / (x^2-3) 3x^2+1 remainder -3x

*March 1, 2011*

**Algebra 2**

I am totally lost! (3x^4--8x^2 -3x-3) / (x^2-3)

*March 1, 2011*

**Algebra 2**

I have been trying to figure this problem out and I am completely lost. Could someone help guide me through it? (3x^4-0x^3-8x^2 -3x-3) / (x^2-3)

*February 28, 2011*

**Physics**

Which of the following is true? a. Conserved forces cannot do work b. Work can be performed on an object without moving it c. If the work is done by a conserved force, you do not need to know the path the object took d. To know the total work performed on an object you must ...

*February 26, 2011*

**Physics**

Suppose the Earth was only half the size it is now (half the mass and half the radius), what would "g" be?

*February 24, 2011*

**Physics**

The gravitational constant for Earth is gE = 9.8m/s2. The gravitational constant for the planet Mongo is 20 m/s2. If an object has a weight of 10 lbs on earth, what is its weight on Mongo?

*February 21, 2011*

**Physics**

The gravitational constant for Earth is gE = 9.8m/s2. The gravitational constant for the planet Mongo is 20 m/s2. If an object has a mass of 10 kg on earth, what is its mass on Mongo?

*February 21, 2011*

**Physics**

The gravitational force between two objects is proportional to what

*February 21, 2011*

**Physics**

A 5 kg block is being pulled to the right by a rope which is attached to a dangling 2 kg mass. The coefficient of kinetic friction between the mass & table is 0.1 What is the tension in the rope?

*February 21, 2011*

**Physics**

A block is sitting on a ramp. The block feels a force of friction sufficient to keep it from sliding down the ramp, which makes an angle of 30 degrees w.r.t. horizontal. What is the minimum coefficient of static friction between the block & ramp?

*February 21, 2011*

**Physics**

Three weights are attached to the corners of an equilateral triangle (side length 10 cm) made from stiff but very light wire. Measured from the bottom left corner, what is the center of mass of this object if M1 = 0.1 kg, M2 = 0.2 kg, and M3 = 0.3 kg?

*February 21, 2011*

**Physics**

A car travels around a circular track (4 km diameter). Its tires have frictional coefficients: mS = 0.3 & mK = 0.2. If the track is flat, how fast can the car travel around the track and still maintain control?

*February 21, 2011*

**Physics**

A lower block is being pulled to the right across a wooden table and it is 5kg and the block on top of it weighs 2 Kg. The friction between the table and the lower block is reduces the total acceleration to be 1.5 m/s2. Friction keeps the upper block attached to the lower one...

*February 21, 2011*

**Physics**

A 5 kg block is being pulled to the right with a 20 N force. This causes the block to slide along the table with an acceleration of 2 m/s2. What is the coefficient of kinetic friction between the block and table?

*February 21, 2011*

**Physics**

A 5 kg block is attached via a rope to a dangle 2kg mass. Consider the case without friction. What angle would the ramp be for the 5kg block to experience zero acceleration?

*February 21, 2011*

**Trig**

find the exact value of the expression using the provided information. Find Tan (S+T) given that cos s=1/3 with s in quad I and sin T= -1/2 with T in quad IV

*February 18, 2011*