# Posts by francis

Total # Posts: 183

**Physics! **

At a steam power plant, steam engines work in pairs, the output of heat from one being the approximate heat input of the second. The operating temperatures of the first are 520°C and 320°C, and of the second 310°C and 170°C. If the heat of combustion of coal is...

**Physics **

A bar of gold and a bar of silver are used to conduct heat from one end maintained at 80.0oC and another end maintained at 30.0oC. If both bars have the same length L = 1.00m and the same cross sectional area A=100cm2 and are insulated from the outside, once steady state has ...

**Physics**

You cool a 100g slug of red hot iron (745oC) by dropping it into an insulated cup of negligible mass containing 75.0g of water, at 20oC. Assuming no heat exchange with the surroundings (a) what is the final temperature of the iron? (b) what is the final mass of the iron and ...

**Physics **

A glass flask with a mass ok 3.00kg and volume of 1000 cm3 is completely filled with mercury and is at a temperature of 55.0oC. The flask is then lowered into an ice water bath. After thermal equilibrium is reached, (a) what percentage of the flask will be filled with mercury...

**Physics **

Standard Temperature and Pressure (STP) is defined as a temperature of 0.00oC and a pressure of 100kPa. If the molar mass M of nitrogen is 14.0 g/mol, find the density (kg/m3) of nitrogen gas (N2) at STP. Nitrous Oxide or laughing gas is composed of the molecule N2O. If the ...

**Physics **

A horizontal pipe is shown and has an area of 40.0 cm2 in wide areas and 10.0 cm2 in narrow areas. It is also connected to a U shaped tube filled with mercury. water is flowing through the pipe at a rate of 5.00 L/s. Find (a) the flow speeds at the wide and narrow portions (b...

**Physics **

1. A cylindrical disk of wood weighing 45.0N and having a diameter of 30.0 cm floats on a cylinder of oil of density 0.850 g/cm3. The cylinder of oil is 75.0 cm deep and has the same diameter of the wood. (a) What is the gauge pressure at the top of the oil column? Suppose now...

**Social studies**

1. A 2. E 3. B 4. E

**Physics**

A cube of ice is taken from the freezer at -9.0°C and placed in a 71-g aluminum calorimeter filled with 261g of water at room temperature of 20.0°C. The final situation is observed to be all water at 13.4°C. What was the mass of the ice cube (in grams)?

**Science**

A uniform have metre rule,pivoted at 20cm mark balances horizontally when a mass of 50g is suspended from 4cm mark calculate the mass of the metre rule.

**science**

Youre travelling down the road in a car with a total mass(including passengers) of 2.24 X 10^3 a)What is the change in kinetic energy of the car if you slow down from 80km/h to 70km/h(reducing your speed by 10km/h) B)what is the change in kinetic energy of the car if you slow ...

**Civic education **

Fundamental human right are said to be inalienable, discuss the limitations of human right

**Physics**

Boxes are moved on a conveyor belt from where they are filled to the packing station 11.3m away. The belt is initially stationary and must finish with zero speed. The most rapid transit is accomplished if the belt accelerates for half the distance, then decelerates for the ...

**Fun Physics**

Unfortunately I wasn't given any other information. I'm thinking that you may have to solve in terms of variables and then the variables may cancel out?

**physics**

what is the minimum effort required to raise a load of 5kg in an ideal pulley system taking gravity to be 10m/s/s

**English**

some have more than a hundred some have none

**physics**

A car A is 300m behind a car B and both are travelling in the same direction at 25m/s. Both cars begin at the same moment to accelerate at steady rate, but A has a greater acceleration and passes B in 20sec by which time B is doing 27•5m/s. Neglecting the length of the ...

**math**

What is the greatest prime factor of 3105?

**math**

97 is the largest prime less than 100. What is the largest prime factor of 97! (97 factorial)? (Reminder: The number n! is the product of the integers from 1 to n. For example, 5!=5*4*3*2*1= 120.)

**Spanish**

correct.

**chemistry**

what is the percentage yield of c2h2 with 50g of cac2 reacts with water to yield 13.5g of c2h2

**Math**

I am a number. Go round the corners of the given figure 4 times. When you add my value with the number of corners you have crossed you get 46. Find my value.

**Math Analysis (Pre Calc)**

A pilot wants to fly 430 miles per hour at 45 degrees north of east, but there is a westerly wind blowing 20 miles per hour. What course correction does the pilot have to make to fly on his desired landing? I wasn't able to figure out any work for this problem could you ...

**applied chemistry**

Draw electron dot diagram for the following compound HCL,CO2,NH3,NH4CL,CH4 And H2O2

**Business**

Assume venture Healthcare sold bonds that have a ten year maturity,a 12 percent coupon rate with annual payment,and a $1000 par value.Suppose that two years after the bonds were issued ,the required interest rate fell to 7 percent .what would be the bond value?

**MATH**

Nicole makes a keychain by using yellow, red and green beads. The number of red beads used is more than twice the number of yellow beads by 10, while the number of green beads used is more than one-third the number of yellow beads by 7. It is known that each yellow bead, red ...

**science**

A tower is 24 m high. A stone is projected upwards from the tower, at a velocitry of 24,5 m/s. Calculate how long it would take the stone to reach the ground at the roof of the tower.

**social studies**

how did the wright brothers change the world a short esssay

**economics**

BIL

**information literacy**

4. Which of the following statements about human-power search engines is true? A. People code the search engine so that they'll populate lists of trending search terms and phrases. B. Links are selected by users. C. Users send in their search request and then the search ...

**Electrical principles**

a. What current is flowing in a 2.0m length of wire in the Earth's field of 55μT if it experiences a force of 10mN? b. A 2 wire cable is suppling 100 A to a DC motor. Each wire has a 2 mm insulation layer and there is also a 2 mm separate insulation layer between the ...

**maths**

Show that r = 1/4 - 3Cos¦È is polar form of an ellipse and find its centre. pls can anyone could help with this.

**Math**

-1^2 = 1 so f(2) = 2*1 = 2. (by multiplication)

**Math**

thanks so much irving

**Math**

is the correct answer 2800 marbles

**Math**

3.Josh has a huge marble collection. He counts 280 marbles that are red, and he estimates that this is about 10% of his collection. A.Write and solve a proportion to estimate the total number of marbles Josh has.

**Math**

thakns irving

**Math**

did she get 53 problems correct

**Math**

Mia took a test with 60 multiple-choice questions. Her teacher told her she got 88% correct. A.Write and solve a proportion to figure out how many questions she got correct.

**Math**

and the proportion answer is 80% right?

**Math**

i think the unknown in this problem is the percent

**Math**

1.A restaurant surveys 60 of its customers about their new menu. 48 of the customers that take the survey prefer the new menu. A.Which value is unknown in this problem: the part, percent, or whole? B.Write and solve the proportion to find the percent of the customers that ...

**math**

4.In Amy’s English class, 30% of the students play an instrument. She does not know how many in the whole school play an instrument, but there are 500 students in the school. A.Solve the proportion 30/100=n/500 to estimate the total number of students in the school who ...

**Science**

you welcome :-)

**Science**

you could put that vinegar has the most density because it sinks to the bottom unlike the oil which has bouyancy that keeps it afloat.

**Science**

yes it's a very reasonable answer

**Math**

3.Max says there were 6 students wearing shorts in his math class. He is not sure how many people were in the class, total, but he thinks about one third of them were wearing shorts. A. What percent is closest to 1/3 ? Explain. B.Write and solve a proportion below, to estimate...

**Math**

ok

**Math**

is that the answer?

**Math**

What is 21.21% rounded to two decimal places?

**maths(direction cosines of vectors)**

find the direction cosines of the vector joining the two points (4,2,2,) & (7,6,14) (this is new to me, used to think it was just one point not two.)

**maths**

What's the coefficient of x^2 in the expansion of (2 - 1/2x)^4 (I've no idea hw to go bout this & I would also like to know under which topic it falls)

**math**

I was d one dat posted d previous question, I had to re-post again cos d plus sign won't show after I click submit

**math**

The line x plus 7y=5 cuts the circle x^2 plus y^2=15 at the points P & Q. Find: a) P & Q. b) the midpoint of PQ. (I don't know why, but the plus sign does not show after I submit d question so dats y I wrote it in words)

**Maths**

there's a plus sign in btw x & 7y, d system prolly removed it. x plus 7y=5 x^2 plus y^2=15

**Maths**

The line x 7y=5 cuts the circle x^2 y^2=15 at the points P & Q. Find: a) P & Q. b) the midpoint of PQ.

**physics(waves)**

A wave has a speed of 340m/s and a period of 0.28ms. what's the wavelength? so I worked this and I got 95.2m but the answer to d question says 0.095m. period(T) = 1/F (since F = 1/T) therefore, F = 1/0.28 = 3.5714 wavelength = velocity/frequency w = 340/3.5714 = 95.2m (Isn...

**Calculus**

If Y = SecXTanX, find y" 4y' 4y. I can easily do the second part of the question if I could if only I could find d first and second derivative of SecXTanX, pls do help.

**Differentiation**

If Y = e^tanx, find dy/dx

**Calculus**

The volume of a solid

**calculus**

lim x->0 (Sin^3 3x - 3x^3)/(x^3) (x^4)

**Math**

Could u show the workings, pls. I knw, I =PRT/100 P=$1600.00 R=7% so which are we looking for, I or T?

**Calculus**

lim x->0 (Sin^3 3x - 3x^3)/(x^3) (x^4)

**Calculus**

Evaluate lim x->0 (Sin^3 3x - 3x^3/x^3 x^4) I got zero (0) to be my answer by imputing 0 in place of x but am not so sure if the answer should be 0, am thinking it should be like 1/0 or something like that.

**Algebra 1**

no, its should be 4.8 ¡Á 10^8

**Calculus**

Find ¡Ò[dx/(x-2)(x+3)(x-4)] this is really confusing and I need help with it.

**Calculus**

differentiate tan-1(2x/1-x^2)

**vectors**

a = (A plus B), b =(B plus C), c =(C plus A)...I add added the plus symbol in between b4 submitting, don't know why it's not show.

**vectors**

Show that a¡Á(b c) = (a¡Áb) (a¡Ác), given that a =(A B), b =(B C), c =(C A). WORKINGS ... given, a¡Á(b c) = (a¡Áb) (a¡Ác) :. imputing the values of a, b and c (A B)¡Á[(B C) (C A)] = [(A ...

**trig**

Sin = Opposite/Hypotenuse, Cos = Adjacent/Hypotenuse, Tan = Opposite/Adjacent. To remember, memorize as SOH, CAH, TOA. Where A = Adjacent, H = Hypotenuse, O = Opposite. Since we were given the opposite side and one angle & we're to find the hypotenuse, therefore, you use ...

**Physics**

Yea, you get to use F=MxA where, M=mass, A=acceleration. if you expand the equation, you notice F=MxA where A=velocity change / time taken for change therefore, f = 1kg x (5ms/5secs)

**Advanced Algebra**

If a pond can support up to 10, 000 fish, the rate of growth of the fish population is jointly proportional to the number of fish present and the difference between 10, 000 and the number of fish present. The rate of growth is 90 fish per week when 1, 000 fish are present. a. ...

**College Algebra**

How to solve this system? x + [(3x-y)/(x^2+y^2)] = 3 y - [(x+3y)/(x^2+y^2)] = 0

**mechanics and fluids**

a block of mass 6 kg resting on a horizontal surface is connected by a cord passing over a light, frictionless pulley to a hanging block of mass 4 kg. the coefficient of kinetic friction between the block and the horizontal surface is 0.5. after the block are released, find ...

**physics**

I don't understand what you tryna say.

**physics**

A solid of mass 1kg suspended by a string is completely immersed in water. If the tension in the string is 5N, calculate the upthrust on the solid. (take g = 9.78m/s)

**physics**

I still don't understand.

**physics**

Calculate the energy required to vapourise 50g of water Initially at 80¡ãC if the specific heat capacity of water is 4.2 J/g.k. (specific latent heat of vapourisation of water is 2260 J/g)

**maths**

2x^2 + 2y^2 - 8x + 5y + 10 = 0

**physics**

Constructive interference will occur, cos constructive interference occurs wen d path difference btw identical waves at a point is n¦Ë...where n = 0,1,2,3... Destructive interference occur wen d path difference btw two identical waves at a point is n¦Ë ...

**Maths (differentiation)**

Differentiate Y = 1/SinX^2

**maths**

Thank you you're awesome

**maths**

factorize completely X^2 + 2X^2 - 15X / 2X^2 - 18

**Maths (factor theorem)**

9x^2 6xy 4y^2 is a factor of 27x^3 - 8y^3, find the other factor.

**Maths**

(243/32)^-1/5 ¡Á 2^-2

**Maths**

if p:q=2/3:1/6 & q:r=3/4:1/2. find p:q:r

**Physics**

The tension in the string provides the centripetal force for objects tied to a string & movin in a circular path. Ft = mv^2/r where m=mass of d object, v=uniform velocity of d movin body & r=radius of d circle formed by d moving string 1 revolution = 360¡ã or 2pie...

**world history**

Search on Google.

**Math**

1 - 2/7 = (7 - 2)/7 = 5/7

**Science 1 question**

If you're doubting check google, I'm positive that it's A.

**Science 1 question**

The answer is A.

**maths/permutation and combination**

Find the number of ways, the digits 0,1,2 and 3 can be permuted to give rise to a number greater than 2000. Please I need an explanatory workings!!!

**Maths (Integration)**

Please can you show an explanatory working, just to be able to work a similar question. thanks

**Maths (Integration)**

Integrate(1+x/x^3)dx Don't know how to go bout this, if the numerator was a whole number it would ve been easier for me, Pls help me out.

**Maths**

Sorry one more thing, how do you get the slope?

**Maths**

Alright, thanks.

**Maths**

ok, can you pls direct me on how to work a similar question?

**Maths**

So the question is wrong?

**Maths**

find the equation of the perpendicular bisector of the line joining P(2, -4) to Q(-5,1) A. 8y-14x 13=0 B. 8y-14x-13=0 C. 8y 14x-13=0 D. 8y 14x 13=0 Please I need someone to help me with this, with an explanatory workings.

**Trig**

angle of 25 degrees is measured, point 'M' our obtuse triangle is then 'TBM' and we also define a point 'G' that is at ground level and colinear with points 'T' and 'B' such that 'MBG' forms a right triangle whose hypotenuse is ...