Tuesday

October 13, 2015
Total # Posts: 738

**Physics**

A beam of light is incident on the surface of clear ice at 60 degrees with the normal. Find the angle between reflected and refracted ray. theda 1=60 n1= 1 (air) What would n2 be for clear ice? I know that index of refraction for water is 1.33. Would it also be 1.33? Snell'...
*April 16, 2008*

**Physics**

Find the speed of light in flint glass if the index of refraction is n=1.66. How much slower in percent of speed of light in a vacuum c does the light move in each of this medium? v=c/n v=3x10^8m/s/1.66 =1.8x10^8m/s For the percent of speed of light in a vacuum c. Would it be...
*April 16, 2008*

**Physics**

Is it possible to see a virtual image? a)no they don't exist b)yes the rays appear to emanate from a virtual image c)yes since almost everything we see is virtual because most things do not themselves give off light, but only reflect light coming from some other source d)...
*April 9, 2008*

**Physics**

an electric field is produced by a a)consant magnetic field b)changing magnetic field c)either a consant or changing magnetic field d)none of the above I choose b) because in a lab we once dealt with something similar to this question but I can't exactly remember whether ...
*April 9, 2008*

**C++ Programming**

how do you convert 2 for binary to decimal using c++ program
*April 9, 2008*

**Physics**

#1 If the inductance in the LC circuit is quadrupled the natural frequency of that circuit will a)increase to 4 times its original value b)increase to twice its original value c)decrease to 1/2 of its original value d)decrease to 1/4 of its original value Isn't the correct...
*April 9, 2008*

**Physics**

You have two identical resistors 50kohm each and a 1.5V battery. Which of the following statements are true a)the current drawn is bigger if the resistors are in series b) the current drawn is bigger if the resistors are in parallel c)the voltage across each resistor is bigger...
*April 6, 2008*

**Physics**

1)An electron moved from point A to point B along an equipotential surface. a)the eclectron performs work in moving from point A to point B b)Work is required to move the electron from point A to point B c)Work is both required and performed in moving the electron from point A...
*April 6, 2008*

**Physics**

The materials with the lowest resistance are called a) conductors b)superconductors c)semiconductors d) insulators I can't decide between a) or b) but if I had to choose one would the correct one be b)?
*April 5, 2008*

**Physics**

1)Several resistors are connected in parallel. If a battery provides constant voltage in this circuit the addition of another resistor in parallel a)increases current through each resistor b)decreases current through each resistor c)doesn't affect the current through any ...
*April 5, 2008*

**Physics**

An electron is placed near a neutron. Which statement best describes the electrostatic force between them? a) there's no force between them since one is neutral b)there's a force of repulsion between them c)there's a force of attraction between them Isn't it a...
*April 5, 2008*

**Physics**

For an electron moving in a direction of the electric field its potential energy _______ and its electric potential _________. Wouldn't the blanks be "increases" and "decreases"? because PE=mgh while V=kq/r
*April 5, 2008*

**Physics**

The equipotential lines inside a parallel plate capacitor a) circles clockwise b)circles counterclockwise c)radiates inwards d)radiates outwards e)runs parallel to capacitor plates f)runs perpendicular to capacitor plates I have narrowed it down to either e) or f) but I think ...
*April 4, 2008*

**Physics**

When discharging a capacitor it will a) loose half of its charge in equal time intervals b) loose a third of its charge in equal time intervals c) loose a quarter of its charge in equal time intervals d) gain half of its charge in equal time intervals I know that d) isn't ...
*April 4, 2008*

**Physics**

1)Several resistors are connected in series. If a battery provides constant voltage in this circuit the addition of another resistor in series a)increases current through each resistor b)decreases current through each resistor c)doesn't affect the current throught any ...
*April 4, 2008*

**Physics**

A circuit with a capacitor took .138s to discharge from its max charge Qmax to half of that max charge once the battery was removed. In this series circuit there also is one resistor with 100 G(ohm symbol). The voltage drop is 12V across the battery. a)How much time would it ...
*April 4, 2008*

**Physics**

A circuit with a capacitor took .128s to discharge from its max charge Qmax to half of that max charge once the battery was removed. In this series circuit there also is one resistor with 100 G(ohm symbol). The voltage drop is 12V across the battery. What is the time constant ...
*April 3, 2008*

**algebra**

m-450=1/4m -450=1/4m-1m -450=1/4m-4/4m -450=-3/4m -450*(-4/3)=m 600=m
*April 3, 2008*

**Physics**

If the TV draws a 150W of power, the dishwasher 1500 W of power and the computer 100 W of power, will a typical 15 A circuit breaker trip if they operate simultaneously on one line? Explain why. Isn't P= IV and P=I^2R and P- V^2/R So wouldn't that mean that as these ...
*April 3, 2008*

**Physics**

When Gorix escaped from Dr. Sloth's ship, his ship started at rest. Gorix immediately set his thrusters to full power, and his ship's acceleration increased by 2 m/s2 every second for 15 seconds. At that point, the ship remained at constant acceleration for another 30 ...
*April 3, 2008*

**Physics**

A sexond smaller metal sphere was positioned near the van de Graff machine. THe sphere was grounded. Did this snaller sphere become charged? How and why? was the interaction between the two spheres attractive or repulsive? Explain. Yes the smaller sphere was charged because ...
*April 2, 2008*

**Physics**

If the TV draws a 150W of power, the dishwasher 1500 W of power and the computer 100 W of power, will a typical 15 A circuit breaker trip if they operate simultaneously on one line? Explain why.
*April 2, 2008*

**Physics**

The following appliances are being used simultaneously: toster oven, TV, computer, three 100 W light bulbs and an iron. Yet the circuit breaker (15 A) has not tripped. Does that necessarily mean that not all of these appliacnces are connected to a single circuit? I am having ...
*March 26, 2008*

**Physics**

A battery with voltage drop of 120V is connected in a ciruit containing both series and parallel. Moving in a clockwise direction. R1= 3 ohms. Suddenly there is a connection of point A to point B. In between these two points is a parallel circuit with R2= 10 ohms and R3=2ohms ...
*March 26, 2008*

**Anatomy and Physiology**

A. Right to left B. proximal to distal C. anterior to ventral D. coronal to transverse The answer is B.
*March 21, 2008*

**Physics**

A battery with voltage drop of 120V is connected in a ciruit containing both series and parallel. Moving in a clockwise direction. R1= 3 ohms there is a connection of point A to point B. In between there is a parallel circuit with R2= 10 ohms to R3=2ohms on the top. On the ...
*March 19, 2008*

**vocabulary-sentences**

I need help doing my sentences By Andrea
*March 11, 2008*

**Physics**

You came across an egg that was a perfect sphere. You placed it in a tub of water and found that it displaced exactly 280,000 cubic centimetres. However, it was floating on the water, and only 72% of the surface area of the egg was below the water line. What was the total ...
*March 6, 2008*

**precalc**

We're not supposed to find it using arctan. We have to get one side to be 2 factors that equal zero when multiplied.
*March 6, 2008*

**precalc**

Solve sinx+cosx=0 Thanks!
*March 6, 2008*

**science**

You came across an egg that was a perfect sphere. You placed it in a tub of water and found that it displaced exactly 280,000 cubic centimetres. However, it was floating on the water, and only 72% of the surface area of the egg was below the water line. What was the total ...
*March 6, 2008*

**physics**

An electric charfe of -3 C is moved from a position where the electric potential is 1 V to a position where the electric potential is -6V. What is the chsange in potential energy of the charge with this change in position? I know that change in PE = k(q1q)/r_2 - k(q1q)/r_1 I ...
*March 5, 2008*

**Physics**

A block oscillates on a spring and passes its equilibrium position with a speed of .157m/s. It's kinetic energy is zero when the block is at the distance of .1m from equilibrium. Assume no friction between the block and the table. v=.157m/s KE =0J when x=.1m a)First I need...
*March 3, 2008*

**Physics**

A violin string is .32m and has a mass of .0005kg. The freqency of the note played is 440Hz. What is the speed of the wave in the string? .5*wavelenght = L wavelength= 2*.32m =.64m v=f(wavelength) =440hz*.64m =281.6m/s b) where must one put one's finger to play a note with...
*March 3, 2008*

**Physics**

A guitar string is .75m and has a mass of .005kg. A standing wave is produced when the string is plucked. a) what is the fifth harmonic if the tension in the string is 90N? v=sqrt(F_t/mass density)= 116m/s f1=v/2L = 116m/s/(2*.75m) =77.3Hz fn=n*f1 f5=5*77.3Hz =386.5Hz and to ...
*March 3, 2008*

**environmental science**

Why does the FEMA (Federal Emergency Management Area) only allow property owners to collect insurance if they rebuild in the same place and same way as before? Thanks!
*March 2, 2008*

**Physics**

A block oscillates on a spring and passes its equilibrium position with a speed of .157m/s. It's kinetic energy is zero when the block is at the distance of .1m from equilibrium. Assume no friction between the block and the table. v=.157m/s KE =0J when x=.1m a)First I need...
*March 2, 2008*

**Physics**

A block oscillates on a spring and passes its equilibrium position with a speed of .157m/s. It's kinetic energy is zero when the block is at the distance of .1m from equilibrium. Assume no friction between the block and the table. Force is 8.67N. Also mass displacement is...
*March 1, 2008*

**Physics**

Why do your vowels examples ("aaah", "eee", "uhh") sound different then when I make them? Explain. Tension, mass density and the length of our vocal cords differ so would that be the reason why they sound different? For instance: a child's ...
*March 1, 2008*

**Physics**

A musician plays the middle C note (262 Hz) on a guitar, a piano, and a violin at the same loudness. Will all three instruments produce exactly the same sound? Why or why not explain. Frequency (262Hz) is the same so that means that the pitch of the sound wave is the same. ...
*March 1, 2008*

**Physics**

Why do ocean waves break as they approach the shore? Is it because of the principle of superposition. Would it be described as constructive or destructive interference? I believe it's constructive interference as the two waves combine the amplitude is large which causes ...
*February 29, 2008*

**Physics**

A block oscillates on a spring and passes its equilibrium position with a speed of .157m/s. It's kinetic energy is zero when the block is at the distance of .1m from equilibrium. Assume no friction between the block and the table. What is the period of its oscillation? v=....
*February 29, 2008*

**Physics**

The frequency of a stationary siren is 1500 Hz when measured by a stationary observer. If an observer moves away from the siren at mach number .85 what is the frequency he hears? (assume room temperature so that velocity of the air is 340m/s) I know that I would use f'=f (...
*February 29, 2008*

**Trig**

Verify that each of the following is an identity. tan^2x-sin^2x=tan^2xsin^2x I can get it down to cos^2 on the right, but cannot get it to work out on the left. secx/cosx - tanx/cotx=1 On the left I got down to 1-tan^2, but that clearly doesn't equal 1.... 1-2cos^2x/...
*February 28, 2008*

**History**

Eisenhower
*February 28, 2008*

**history**

what is the slaves experiences in mid19th century america
*February 26, 2008*

**american history**

what businesses came under the scrutiny of the sherman antitrust act in the 1800s?
*February 18, 2008*

**precalc**

thanks
*February 18, 2008*

**precalc**

Hi. Can someone help me with this? Simplify: (sin^2x)(cos^2x)+(sin^4x) The answer is sin^2x, but I have no idea how to get there! Thanks!
*February 18, 2008*

**science**

Suppose you have monohybrid pea plants in your garden and find that they produce round seed to wrinkled seeds in the ratio of 3:1. If the allele are designated (R & r) respectively, what is the probable genotypes of the wrinkled seeds which were produced (F1)? RR & Rr RR only...
*February 15, 2008*

**Math**

Find the value of tan(1/2sin^-1 15/17) and sin[pi/2-cos(1/2)] Thanks.
*February 13, 2008*

**Math**

how would you factor 4x-x^2-3/ x-1...so that x-1 would cancel out? could you explain step by step..plz
*February 8, 2008*

**Physics**

A string of mass m=.1kg is stretched to where its length is L=20m. What is the tension force applied to the string if it takes a pulse 2 seconds to get from one end to the other? m=kg L=20m T=4s mass density =m/L = .1/20 = kg/m Tension =? I know v=sqrt(F_t/mass density) But I...
*February 6, 2008*

**Physics**

Find the instantaneous velocity of a pendulum at the instant when its bob is at the height equal to half of its maximum height h=(h_max/2) above teh equilibrium point. Assume the max velocity of the bob during each oscillation is v_max= 2m/s. Wouldn't PE=KE mgh=1/2mv^2 gh=...
*February 6, 2008*

**Physics**

A swing is 2m long. how often do you need to push it to increase its swing's amplitude the most? L=2m When amplitude is the most KE=0 and PE is at its maximum. But i'm not completely sure how to solve this problem.
*February 6, 2008*

**Physics**

A mass m=.5kg on a spring with a spring constant. It is displaced by the distance x_max =20cm (.2m) from equilibrium on a frictionless horizontal surface. At the time t=0s the mass is released and it begins to oscillate. Assume that T=3.14s. Find the following for when t=0, T/...
*January 30, 2008*

**Physics**

Find the instantaneous velocity of a mass on a spring oscillating on a horizontal frictionless surface at the instant when its displacement is half of its maximum displacement x=(x_max/2). Assume the max velocity of that mass during each oscillation is v_max= 2m/s. I know that...
*January 30, 2008*

**Math**

Which type of dilation is determined by a scale factor of 10? enlargement reduction congruence transformation none of these
*January 15, 2008*

**math**

how would you solve for x? can you explain step by step? 40 = [(x+2.8)/2]*8.5
*January 12, 2008*

**Math : Algebra**

how would you solve for x? can you explain step by step? 40 = [(x+2.8)/2]*8.5
*January 11, 2008*

**Math : Algebra**

how would you solve for x in this equation? 40.0 = 0+ (x + 2.8)/2multiplied by(8.50)
*January 11, 2008*

**history**

Why did Germany invade Poland in 1941? =]
*January 3, 2008*

**History**

Why did Japan invade China in 1937? thank you so much =]
*January 3, 2008*

**History**

Why did Japan invade China in 1937? thank you so much =]
*January 3, 2008*

**Bio**

Describe what can happen to the three-carbon molecules made in the Calvin cycle.
*December 1, 2007*

**Physics**

A box of mass 1kg is placed on a table and is connected to a hanging mass m by a string strung over a pulley. If the coefficient of kinetic friction between the box and the table is .3 and the box slides at a constant speed of .5m/s what is the weight of the hanging mass? to ...
*November 14, 2007*

**Physics**

You have just discovered a planetary system consisting of a star (Dagobahr) and its two planets: Rool and Krau. Planet Rool has an average orbital radius 3 times as big as planet Krau. If planet Rool orbits Dagobahr in 2 earth years (1earth year = 365 days). a) how long is the...
*November 14, 2007*

**Physics**

A box of mass 1kg is placed on a table and is connected to a hanging mass m by a string strung over a pulley. If the coefficient of kinetic friction between the box and the table is .3 and the box slides at a constant speed of .5m/s what is the weight of the hanging mass? ...
*November 14, 2007*

**Physics**

A box of mass 1kg is placed on a table and is connected to a hanging mass m by a string strung over a pulley. If the coefficient of kinetic friction between the box and the table is .3 and the box slides at a constant speed of .5m/s what is the weight of the hanging mass? ...
*November 14, 2007*

**Physics**

complete the statement: in recoil a)the initial momentum is zero b)the object sticks together after collision c)the total kinetic energy is conserved d)the final speeds of the object are the same b) is wrong. I think it's either c) or d) but i'm going to go with c).
*November 14, 2007*

**Physics**

a rock is thrown straight up which of the following statemetns concerning the net force acting on the rock at teh top of the path is true? assume air resistance is negligible. a)it's equal to the weight of the rock b) it is instantanwously equal to zero c) it's ...
*November 14, 2007*

**Physics**

two objects collide when sliding on a fricitonless horizontal surface. Which quantity is conserved during their collision? a) velocity b) momentum of both objects c)energy d) momentum of each object isn't c) or b) correct? I really think it's c)
*November 14, 2007*

**Physics**

a rock suspended from a string moves downwards at constant a=g. Which of the following is true concerning the tension in the string? a) the tension is zero b)the tension is equal to the weight of the rock c)the tension is less to the weight of the rock d)the tension is greater...
*November 14, 2007*

**Physics**

Complete the following statement: The term net force most accurately describes: a) quantity that causes displacement b) quantity that keeps the object moving c) the mass of the object d) the quantity that changes the velocity of an object c) is not the right choice. I believe ...
*November 14, 2007*

**Physics**

Europa, a moon of Jupiter has an orbital diameter of 1.34x10^9m and a period of 3.55 days. What is the mass of Jupiter? d=1.34x10^9m T=3.55days = 30672s M=? r=71492000m rm=6.7x10^8 r-total=7414492000m r^3/t^2=GM/4pi^2 741492000^3/306720^2=6.67X10^-11(M)/4pi^2 I got m=2.56x10^...
*November 12, 2007*

**Physics**

The mean radius of the Earth is R=6.38x10^6m. At what distance above the Earth's surface will the acceleration of gravity be 4.905m/s^2? F_g=(Gmme)/r^2 4.905=6.67x10^-11(5.98x10^24)/r^2 The mass cancel out so that is how I got the above answer. r=9017663m Is this the ...
*November 12, 2007*

**Physics**

A 2.1kg brass ball is transported to the Moon. a)What is the mass of the brass ball on the earth and on the moon? Wouldn't it be 2.1kg for the earth as well as for the moon? b)Determing the weight of thee brass ball on the earth. F_g=(G*m_ball*m_earth)/r^2 =20.58N c) the ...
*November 12, 2007*

**Physics**

"the total angular momentum of an object changes when a net external force acts on the system." This statement is: a)always true b) never true c) sometime true, it depends on the force's direction d)sometime true, it depends on the force's point of ...
*November 7, 2007*

**Physics**

A lever is 5m long. The distance from fulcrum to the weight to be lifted is 1m. If the worker pushes on the opposite end with 400N, what is the max weight that can be lifted? l=5m h=1m F=400N F_g=? torque=F_g*l I first must find torque so that I can plug it into the above ...
*November 7, 2007*

**Physics**

Is the answer to this 4? If the filament resistance in an automobile headlamp is 3 ohms, how many amps does it draw when connected to a 12-volt battery?
*October 27, 2007*

**Physics**

Consider a roller coster car moving along a track from point A to point B to point C. a)if the roller coaster car starts from rest at point A (30m above the bottom of a dip (point b). What would be the speed of the car at the top of the next hill (point C), which is 20 m above...
*October 17, 2007*

**Physics**

If the net work done on an object is positive then the object's energy is ...? The object's energy would also increase since W= energy right? The object's energy wouldn't increase or decrease.
*October 17, 2007*

**Physics**

Compared to yesterday you did 3 times the work in one third the time. To so so your power output must have been: a) the same as yesterday's power output b)one third of yesterday's power output c)3 times yesterday's power output d)9 times yesterday's power ...
*October 17, 2007*

**Physics**

A force of 20 N is applied horizontally to a 1 kg mass on a level surface. The coefficient of friction is .2. if the mass is moved a distance of 5m what is the change in KE? W= change in Ke Fd= Change in KE (20)(5)=Change in Ke 200 J =change in Ke But the thing is how would I ...
*October 17, 2007*

**Physics**

A 1000kg car accelerates from 0 to 25m/s in 8s. What is the average power delivered by the engine? (1hp=746W) P=W/t p=Fd/t P=Fv p=mav =1000(25/8)(25) =78125W which is about 104.725 hp Is this correct?
*October 17, 2007*

**Physics**

A ball falls from the top of a building . through the air(air resistance is present) to the ground below. How does the KE just before hitting the ground compare to the PE at the top of the building? Isn't KE and PE equal to each other in this situation? Since I believe ...
*October 17, 2007*

**Physics**

What work is required to stretch a spring of spring constant 500N/m from x1=.2m to x2=.25m? Assume the unstreched position is at x=0. W=Fd so w=(500)(.25-.2) =500(.05) =25J is this correct? Calculate the work required to compress an initially uncompressed spring with a spring ...
*October 17, 2007*

**Physics**

If your last electric bill for sept. was $105. If the average price is 6.5 cents per kw, how many kw did your household use in September? 1kw/.065 = x/$105 .065x=105 x=1615.38 kw is this correct? How many Joules is that? I know that 1W =1Joule/second 1kw=1000W so 1615.38kw /...
*October 17, 2007*

**Physics**

A 15 N force is needed to move an object with constant velocity of 5 m/s. What power must be delivered to the object by the force? I konw that P=W/t and W=Fd But other than that I am confused . I am not sure how i would solve this problem.
*October 16, 2007*

**Physics**

A wooden block is moving on a rough level surface. It originally has 25J of kinetic energy. If the friction force acting on it is a constant 1N how far will it slide before comming to a stop? KE=F_f 1/2mv^2=F_n (meu) but the problem i run into is that meu and the mass isn'...
*October 16, 2007*

**Physics**

A 50kg skier pushes off the top of a hill with an initial speed of 5m/s. Neglect friction. How fast will he be moving after dropping 20m in elevation? I was wondering if i did this problem correct. PE + KE_f = KE_i mgh +1/2mv_f^2 =1/2mv_i^2 50(10)(20) + 1/2 (50)v_f^2 = 1/2(50...
*October 16, 2007*

**Physics**

A 50kg skier starts from rest from the top of a 100m slope. What is the speed of hte skier on reaching the bottom of the slope? Neglect friction. would i do this: =PE + KE =mgh +1/2mv^2 =50(10)(100) + 1/2 (50)v^2 =50000 +25v^2 =2000 =v^2 44.7m/s =v Is this correct? Thank in ...
*October 16, 2007*

**english**

what is cultural blindness
*September 26, 2007*

**MATH/GEOMETRY!**

HElp me !!!!!!! Malia told Lucia that she had figured out a pattern for computing the number of 3-letter names for any plane if she knew how many letters were named on the plane. For example, if there were four points, there were 4x 3x 2x 1 names possible. lucia said this ...
*September 17, 2007*

**Algebra 1**

HOW DO U TABLES,GRAPHS,MAPPING DIAGRAM?
*September 10, 2007*

**English**

In An American Childhood how does Annie Dillard reference life or death through the waterfall scene on page 150
*September 8, 2007*

**math**

Line L contains the points given in the table below. If the slope of line m is 1/3 the slope of line L what are three points that could be on line m? x 1 2 3 y -7 5 17 A.(1,-2),(2,10),(3,22) B.(1,-7),(2,3),(3,1) C.(1,-7),(2,2),(3,6) D.(1,-7),(2,2),(3,22)
*August 27, 2007*

**Algebra**

: if the quotient 3m^2 +15m / m^2 divided by 30/ m^2 + 5m is simplified to lowest terms, which of the following is the denominator of the resulting expression? the options are 10 30m^2 m^2 +5m or m^2( m+5) 10, with the restriction that m cannot be zero.
*July 25, 2007*

**algebra 1 I NEED HELP!!**

the bottom of a 25-foot ladder is placed 7 feet from a wall. How far will the ladder reach up? Since the ladder, wall, and ground form a right triangle, you can use this formula: A squared + B squared = C squared A = 7 feet C = 25 feet B = distance the ladder will reach 49 + B...
*July 16, 2007*

**business**

You work in the Human Resources department of your organization. You have been charged with recruiting a manager for a department within the Services division. The Vice-President of the Services division stresses to you that "This department hasn’t had a good manager...
*May 22, 2007*