Arora

whats the celstial sphere?

15 years ago

Hi, so i reallllyy need help, i have an assignment that i have to complete, but the thing is theres a file and this site doesn't allow links, so does anyone have email to help me if you can help i will greatly appreciate it i'll email you the file. btw th...

10 years ago

When an airplane leaves the runway, its angle of climb is 24° and its speed is 345 feet per second. How long will it take the plane to climb to an altitude of 10,000 feet? 16,000 feet? (Round your answers to one decimal place.) 10,000 ft = ? in s 16,000 f...

8 years ago

Which one is more stable, [PCl4]+ or [PCl6]- ? Why? I'm thinking it has something to do with the fact that the former is tetrahedral and the latter is octahedral, but I'm not sure. Does that affect stability?

7 years ago

Consider a cube of side 100cm. Consider two diaganolly opposite points (the main body diagnol) as A and B. The cube is kept flat on the ground, and is filled with water upto a 40cm height. Now, the cube is tilted such that AB is vertical. What's the heigh...

7 years ago

that reading material could be inappropriate. the students could pick reading materials that are inproper.

15 years ago

okay, i understand.

10 years ago

A smokestack is 180 ft high. A guy wire must be fastened to the stack 30.0 ft from the top. The guy wire makes an angle of 42.0° with the ground. Find the length of the guy wire?

8 years ago

A rectangular piece of sheet metal is 4 ft longer than it is wide. (See the illustration.) The area of the piece of sheet metal is 45 ft2. Find its length and width?

8 years ago

1(x-0)^2 + (-5) a = 1 h = 0 k = -5

7 years ago

Step 1: Using equation of motion 3- v^2 = 2as v^2 = (2)(10)(440) = 8800 Step 2: Kinetic energy = (1/2)mv^2 = (1/2)(4)(8800) (Because 9 pounds is 4 kgs) = 17600 J Step 3: Kinetic energy = Electical Energy = E = 17600J E/t = P t = E/P t = 17600/100 = 176 Th...

7 years ago

Case A: Taking your mass as M Mass of the ball as m Initial ball speed as u Final combined speed as v: Using conservation of momentum - Initial momentum = Final momentum mu = (M + m)v 0.405*11.5 = (71.5+0.405)V V = 4.6575/71.905 = 0.0647 m/sec = 6.47 cm/s

7 years ago

The element oxygen gets hydrogen added to it Since reduction is defined as the addition of hydrogen or the loss of oxygen (in this case the addition of hydrogen), O2 is being reduced.

7 years ago

Perimeter of the field = Total cost/Cost per meter = 432/15 Length of four sides = 432/15 Length of one side = (432/15) * (1/4) = 432/60 = 36/5 m

7 years ago

Step 1: Considering the gas equation for the first condition: PV = nRT n = PV/RT = 1*1.5/0.0821*273 = 1.5/22.41 = 0.066 mol So we now know that the number of moles of CO2, which will remain fixed, is 0.066 mol. Step 2: In the new case - Total mass of CO2...

7 years ago

It would help with visualising if you drew block diagrams for the question. Net force on B = downwards weight (mg) and upwards Tension (T) Net force on A = down the incline weight (mgsinθ) and up the incline Tension (T) I'm gonna take mass of A as M, and...

7 years ago

S.I. = P * R * T = 600 * 0.036 * 12 = 259.2 Rate of interest = (S.I/P)*100 = (259.2/600)*100 = 43.2%

7 years ago

1. Similarity in triangles refers to equal angles. An equilateral triangle will always have all three angles being at 60 degrees, whereas a scalene triangle will have different values for all angles. So the answer is - never true 2. In order for two polyg...

7 years ago

S.I. = (PRT)/100 Final amount = P + SI = P + (PRT)/100 = 150 + (150*4*T)/100 To double itself: 300 = 150 + (150*4*T)/100 150 = (150*4*T)/100 100 = 4T T = 25 Hence, it will take 25 years

7 years ago

-13y - 6 = 18x => -13y = 18x - 6 => y = (-18x/13) - (6/13) Comparing it to y = mx + c (the slope-intercept form) => m = (-18/13) => c = (6/13)

7 years ago

To find the reciprocal of a number, you switch the numerator and denominator. So the reciprocal is 11/9. (A more accurate definition, is that the reciprocal when multiplied with the original number results in 1)

7 years ago

All electromagnetic waves travel at the same speed. The only difference is in wavelengths and frequency. So the speeds will all be the same.

7 years ago

u = 17.4m/s, a = -1.8m/s^2 v = 13.4m/s Using the first equation of motion: => v = u + at => (v-u)/a = t => -4/-1.8 = t => 2.22 seconds

7 years ago

Thank you very much for your opinions!

7 years ago

I assume that the heat produced is 180,000 Joules and not kilograms, since Joules is the unit for energy Calorific value = Heat energy Produced/Mass of fuel = 180,000/4.5 = 40,000 J/kg

7 years ago

2(H2) + O2 --> 2(H2O) You can see in the reaction that two moles of hydrogen react with two moles of oxygen. So if you have the save amount of both, which will finish first? So which is the limiting reagent?

7 years ago

*one mole of oxygen

7 years ago

If the entire function g(x) is an integral with upper and lower limits, that makes it a definite integral. A definite integral always has a constant value. That would make g(x) a constant value. So what would its derivative be? (This might be incorrect if...

7 years ago

If after 30 seconds there are 14 gallons left, and after 60 seconds there are 9 gallons left, Then you can see that in the 30 second gap, 5 gallons leaked out. So water is emptying at 5 gallons/30 seconds or 1 gallon every 6 seconds. Can you use this rate...

7 years ago

NOPE STOOPID

7 years ago

Since t is a variable, you can obtain three different points on the plane: a) (0,2,-1) Given in the question b) (2,4,-6) by setting t=0 c) (3,5,1) by setting t=1 If you know three points in a plane, you can use them to find a unique equation for the plane...

7 years ago

In order to find the volume of the cylinder, you also require its height.

7 years ago

The maximum sum of two digits in the number (first and last) can be 18. Thus, the middle digit cannot be larger than 4 (since that would be larger than 1/4th the largest sum). Since reversing the number increases it, the third digit is larger than the fir...

7 years ago

Average Speed = Total Distance travelled/Total time taken You've been given a distance of 290km, and a time of 1 hour 15 minutes, which is 1.25 hours. Can you put these values into the formula?

7 years ago

You're almost correct with the balanced equation for photosynthesis: 6H2O + 6CO2 = C6H12O6 + 6O2 For every 6 moles of water the plant takes in, it produces 1 mole of glucose. A kilo of water = 1000g Number of moles of water = 1000/18 = 55.55 Number of mol...

7 years ago

The sodium chloride initially converts into Na+ and Cl- ions upon being added to water. These Cl- ions undergo electrolysis to form chlorine. However, the mass of chlorine shall remain constant throughout the process, and so the mass of Chlorine produced...

7 years ago

If you take the amount of $410 perfume to be used as x ounces, the amount of $250 perfume to be used becomes (40-x) ounces. For the final mixture to be worth $300 an ounce: 410x + 250(40-x) = 300(40) Solve for x

7 years ago

This is very similar to the other question you asked, where I've put up a solution. Give this one a go and a tutor will check your work!

7 years ago

If three vectors are coplanar, their scalar triple product is zero. Give it a go, and someone will check your work :)

7 years ago

Try figuring out how much of the task each man can do in one hour, as a fraction. You can use that to find out the work done in an hour if all three work together, and thus the amount of time it will take.

7 years ago

You've already posted the exact same question, to which I replied. You also posted an earlier, similar question, which was answered. Did you not learn from the process on the other question?

7 years ago

I agree with C.

7 years ago

Yes, A is correct.

7 years ago

The first step would be to form an equation for the given information. Let's take the amount saved last week as x. Since we're told that $200 is $50 more than twice the amount saved last week, we can write: 2x + 50 = 200 Now you can solve for x.

7 years ago

Just a tiny correction, the formula (V^2+v^2+2Vvcos120) will give you the square of the resultant speed, not the speed itself.

7 years ago

I believe it has to do with the friction that occurs as a result of driving. Friction causes heat, and once the air molecules are heated, they increase the pressure in the tyre by striking its walls with a greater force per unit area.

7 years ago

For your first answer, the exact value if 2.148, which when rounded off gives 2.1, not 2.3. The other questions are correct!

7 years ago

There are six interspecific relationships, as for symbiotic relationships, the term used is 'mutualism'. You could use the example of lichens to explain this.

7 years ago

The sum of the given sides must be equal to 22, the perimeter. Therefore, (3x + 1) + (2x + 1) + (x + 4) = 22 => 6x + 6 = 22 Solve for x, and you can find the values of the three sides.

7 years ago

Have you given it any thought? Take the first function as (-x^2-1) and the second as (x^2-1)^2, and use the quotient rule for differentiation: d(u/v)/dx = (u'v - v'u)/v^2

7 years ago

The angles 37, 52, and 90 correspond to a 3,4,5 sided right angled triangle. Using that information, you can take tan37.5 = 3/4 Use a calculator for a more accurate value.

7 years ago

'To your bed' should mean near the bed, the second option. In order to say that you are on the bed, 'onto your bed' would have been used.

7 years ago

The given line can be rewritten in the form y = mx + c : y = -(2n+3)x/n + 4/n Here, 'm' is the gradient of the line. m = -(2n+3)/n If a line perpendicular to this line has a slope n, then, m = -1/n So: -(2n + 3)/n = -1/-0.2 => (2n +3) = -5n => 2n + 3 = -5...

7 years ago

(27\8)A+7=(4\9)-3A => (27/8)A + 3A = (4/9) - 7 => A((27+24)/8) = (4-63)/7 => (51/8)A = -59/7 => A = -(59/7)*(8/51)

7 years ago

Power = Work Done / Time Work Done = Change in Potential Energy Change in Potential Energy = mgh Therefore, Power = mgh/t = 10*5*9.8/5 = 98 W

7 years ago

a) Each team plays every other team in the division Number of games = 7C2 = 21 b) Each team plays two teams from the other division Total number of games = 14 (When one team plays another, both of them have one out of the two needed games completed. Seven...

7 years ago

Area = Length * Breadth Now we know that the perimeter in this case is of three sides i.e.: 2(Breadth) + Length = 25 So if the breadth is x, the length is 25-2x So, area = x(25-2x) = 25x - 2x^2 Taking f(x) = 25x - 2x^2 f'(x) = 25 - 4x f''(x) = -4 Equating...

7 years ago

Yes, you are correct, it shows the associative property of addition.

7 years ago

Inertia is basically the tendency of an object to oppose a change in its state. Mathematically, inertia is proportional, or even equal, to mass. You can understand this as 'it's harder to move an elephant than a rat'. Thus, an elephant experiences more in...

7 years ago

Greatest common divisor, I presume. a + b = 77 Since a and b are both divisible by seven, 7p = a 7q = b => 7(p +q) = 77 => p + q = 11 So if you take any two values for p and q the sum of which is 11, you will get the two required values of a and b.

7 years ago

Molality = number of moles / mass of solvent Consider 100ml of the given solution. It has 135.4 g of sulphuric acid. M.M. of sulphuric acid = 98g Number of moles in this case = 135.4/98 = 1.31 Molarity = number of moles/volume of solution (in Liters) = 1....

7 years ago

Then you are any of the following numbers: 100, 150, 200, ... , 900, 950

7 years ago

Oh whoops, I accidentally went with three digit, my bad

7 years ago

If 1sq inch = 20sq feet So, if I take a side of 1 inch in my model, it will correspond to √20. Because 1 inch * 1 inch = 1 sq inch And √20 feet * √20 feet = 20 sq feet Scale factor = Larger length of segment/Smaller lenght = √20 feet/1 inch = √20*12 inche...

7 years ago

Law of multiple proportions: "When two elements combine with each other to form more than one compound, the weights of one element that combine with a fixed weight of the other are in a ratio of small whole numbers" =>12.7g of chloride X has 7.1g of Cl =>...

7 years ago

The figure can be imagined as a smaller rectangle (the room) inside a larger rectangle (room plus verandah). Area of veranda = Area of outer rectangle - Area of room If you draw the figure, you'll see: Length of outer rec. = (5+2x) Width of outer rec. = (...

7 years ago

If you take the number of pencils as x, then the given ratio and the number of pens to pencils is proportional. => 4/9 = 100/x => x = (100/4)*9 => x = 25*9 => x = 175

7 years ago

If we take the total number of children in the hall as C, then, Number of girls = (4/7)C Number of boys = (3/7)C We've also been given the difference, so: (4/7)C - (3/7)C = 12 => (4/7 - 3/7)C = 12 => (1/7)C = 12 => C = 12*7 => C = 84

7 years ago

a) f(x) = (x^2 - 9)/(x+3) = (x^2 - 3^2)/(x+3) = (x+3)(x-3)/(x+3) = (x-3) Since this function is a linear one, it'll be continuous at all points. b) Using the similar identity as above, f(x) = (x+3), for x =/= 3 Now, at all points except 3, the function is...

7 years ago

There are 52 cards in a deck, 4 of which are nines. Initially, the probability of pulling a 9 can be represented by P1, and can be found as: P1 = Number of 9s/Number of cards = 4/52 = 1/13 After this, if we pull out a nine (since we want both cards to be...

7 years ago

Yes, that is correct.

7 years ago

The pressure is actually very immense, you have 10km of atmosphere above you. The reason this pressure does not crush us is not because it lacks the magnitude, but because our body's internal blood pressure is designed to negate its effect. As per me, the...

7 years ago

However, pressure is a scalar, not a vector, so I get the feeling that the 'all directions' factor shouldn't cancel anything out, so I'm not too sure about (d). Nevertheless, I'd like to hear one of the tutors' opinions on this.

7 years ago

bobpursley: Yes, but I'm unable to understand how those characteristics of gases are what prevent us from being crushed by the atmosphere, rather than our internal pressure.

7 years ago

You can factorize your given polynomial as follows: x^2 - x - 2 = 0 => (x + 1)(x - 2) = 0 The roots are thus x = 2, x = -1 Alpha = 2, beta = -1 Coming to the next part, (2alpha + 1) = 5, (2beta + 1) = -1 You can thus use these roots to form the following...

7 years ago

You will use the conservation of momentum for this question. Mass of bullet = m = 0.005kg Mass of ball of lead = M = 10kg Initial speed of bullet = u Final combined speed = v = 0.5m/s As per conservation of momentum, mu = (M+m)v => (0.005)u = (0.005+10)(0...

7 years ago

a) Initial potential energy of the system = k(q1)(q2)/r Final potential energy of the system = k(q1)(q2)/2r Work done = Energy Required = Loss in potential Energy of the system k(q1)(q2)/r - k(q1)(q2)/2r = k(q1)(q2)/2r = (9*10^9)*(3.2*10^-7)*(4.8*10^-7)/4...

7 years ago

b) The potential is a scalar, and can simply be added up. Total Potential = k(q1)/(r1) + k(q2)/(r2) At the point midway, both distances are half of 2r, that is, r1 = r2 = r => Potential = k((q1)/(r) + (q2)/r)) = (k/r)((3.2 - 4.8)*10^-7) = -(9*10^9)(1.6*10...

7 years ago

a) dV/dr = E => V = E*r => V = 10^2 * 10^-2m = 1V b) Change in potential energy = U = qV Charge on a proton = q = 1.6*10^-19 U = (1.6*10^-19)*V = (1.6*10^-19)*1 = 1.6*10^-19J

7 years ago

3/14 multiplied by four is 12/14, which is 6/7 of a week. Since a week has seven days, 6/7 of a week is six days. Each day has 24 hours. Six days in hours: 6*24 = 144

7 years ago

In both questions, your method should first be to find the cost/distance for one bag/one minute, and then multiply for the given amount. a) If you pay 56.25 for 15 bags, then you pay (56.25/15) for 1. If you pay (56.25/15) for 1 bag, then you pay (56.25/1...

7 years ago

Let's first consider the probability of picking two white mugs from the given back. Probability of first white mug = White/Total = 4/7 Probability of second white mug = White/New Total = 3/6 = 1/2 So, the probability of picking two white mugs in a row fro...

7 years ago

This is a bit tough to type here, so I'll explain the process rather than giving the answer directly. First, find the distance between the two given points using the co-ordinate distance formula. Using the same distance formula, taking (0,0) as one point...

7 years ago

The major factor that affects intensity of absorption is the frequency. Atoms only absorb certain discrete energies of incident waves, based on the energy levels of their electrons. Since frequency and energy of the incident waves are proportional, this m...

7 years ago

Using the identity arctanA + arctanB = arctan((A+B)/(1-AB)), arctan(1/4)+ arctan(1/9) = arctan((1/4 + 1/9)/(1 - 1/36)) = arctan(13/35) Now, Using the identity arctanx = (1/2)arccos((1-x^2)/(1+x^2)) => arctan(13/35) = (1/2)arccos(1-(13/35)^2/1+(13/35)^2) =...

7 years ago

First, lets see how many books we can keep in the shelves. Each shelf = 28 books Number of shelves - 3 Total books = 28 x 3 = 84 We have a total of 85 books, but 84 are in the shelves. Thus, 85 - 84 = 1 book is in the stack.

7 years ago

Number of atoms per cubic meter = (Mass per cubic meter/MM)*Avagadro's No. = (8.93*10^3/63.5*10^-3)*6.022*10^23 = 8.4*10^28 Hence, the number of atoms in free electrons in each cubic meter are almost the same, and the answer is one.

7 years ago

I might even be so bold as to say THAT much.

7 years ago

Assuming that you mean: "A car travelling at a speed of 30km/h is bought to rest in a distance of 8m by applying brakes. If the same car is moving at a speed of 60km/h, then the distance in which it can be brought to rest with the same brakes is?" In the...

7 years ago

You could also directly say using the same equation that the stopping distance varies with the square of the initial speed, and hence when the initial speed is doubled, the stopping distance is four times as much.

7 years ago

Taking the number as x, Product = 4x Square root of product = √(4x) = 2√x As per the question, Square root of product = 26 => 2√x = 26 => √x = 13 => x = 13^2 = 169

7 years ago

Using the pythagoras theorum, x^2 = (28)^2 + (15.7)^2 x^2 = 784 + 246.5 x^2 = 1030.5 x = Root(1030.5) = 32 The answer is actually closer to B, 32 inches.

7 years ago

Molarity = number of moles/Volume in liters => Number of moles of NaOH = M * Vol = 0.5*0.5 = 0.25 Mass required = Molar Mass * Number of moles = 40 * 0.25 = 10g

7 years ago

2sec^2x - 3tanx - 5 = 0 => 2(1+tan^2(2x)) - 3tanx - 5 = 0 => 2tan^2(2x) - 3tanx - 3 = 0 => (2tan2x + 1)(tanx - 2) = 0 => 2tan2x = -1, tanx = 2 => tan2x = -1/2, tanx = 2 => x = 1.107, 4.249, x = 1.339, 2.91, 4.481, 6.051

7 years ago

If 'rps' here stands for revolutions per second, then you must convert it to radians per second first, otherwise 20cm/sec is correct Centripetal force = mv^2/r = 0.015*0.2*0.2/0.1 = 0.015*0.4 = 0.006 N Gotta convert your units

7 years ago

Equation of a circle: (x-h)^2 + (y-k)^2 = r^2 Where (x,y) is a point on the line and (h,k) is the center. If the center is on the x-axis, then k = 0 => (x-h)^2 + y^2 = r^2 We've been given two points. In both, the radii will be the same, so, (x1-h)^2 + (y...

7 years ago

I'm not sure how tutors here can be of much help without the diagram for this one. Though I suppose you're supposed to equate the potential drop across the circuit with that of the PRT, since the Voltmeter reads zero.

7 years ago

NaCl has an fcc structure. This implies that in an RbI crystal lattice, the distance between cation and anion (ionic radii) is half the diagnol of the unit cell. Hence, if ionic radii = r => √2a = 2r => a = √2r

7 years ago

b) d = (Z)(M.M)/(Na)(a^3) You'll find 'a' in the above part. Note that Z = 4 for an fcc lattice. c) & d) Repeat the same procedure for CsCl which is a bcc structure.

7 years ago

For the first part: 1. centimeters (because it's smaller than a meter, it fits in your hand) 2. and 3. Meters (because these are several meters in length) The second part: 1. Kilograms 2. Grams 3. Milligrams 4. Kilograms

7 years ago

Cost price = 250 per 100 pencils = 250/100 per pencil = 2.5 per pencil Selling Price = 1.75 per pencil => (SP/CP)*100 = ((1.75)/(2.5))*100 = 70% Since the selling price is 70% of the cost price, he loses (100-70)% = 30%

7 years ago

9/10 = 0.9 Negative numbers are smaller than zero and positive numbers, so -0.11 is the least. Zero is less than the other positive numbers. 0.67 is less than 0.9 So, -0.11 < 0 < 0.67 < 0.9

7 years ago

I think you have a typo in your equation Did you mean 24 + (5x) = 13 ?

7 years ago

Density = Mass/Volume => Density = 2.7*10^3kg/m^3 => Volume = l*b*h = 1*0.6*0.3 = 0.18m^3 Mass = Density*Volume = 2.7*0.18*10^3 = 486kg

7 years ago

Sure, you have to ask the question first though

7 years ago