Thursday
October 30, 2014

Posts by don


Total # Posts: 496

Hydraulic Physics
20/25 = F/50 F = (20/25)*50 F= 40 N
October 29, 2014

Hydraulic Physics
No need for gravity. F1/Area1 = F2/AREA2 Solver for F1
October 29, 2014

Dudas
They key thing you need to know is what the center of mass formula is. Center of mass: (m1*x1+m2*x2)/(m1+m2) So at initial center of mass: (86*9+55*2)/(86+55) = 6.27 m So now do apply the same equation when they switch position: (55*9+86*2)/(86+55) = 4.73 m So now find the ...
October 29, 2014

Physics
How did you start this problem?
October 29, 2014

Physics
Just a quick question… Did this problem come with a figure? I can't tell if those angles are along the horizontal or vertical.
October 28, 2014

physics
Veocity = distance / time You are given a distance of 40m and time of 1.9s
October 28, 2014

physics
When doing these types of physic problems or actually any physics problem, write down what's given. m=57.5 kg v_f= 58.9 m/s v_i = 0 (because it was a rest, not moving) t = 14.4 s g=9.81 m/s^2 The apparent weight is: W = F + m*g F=ma Everything is given to us in the problem...
October 28, 2014

Algebra
I almost agree with Aaliyah. Expressions do not need an equal sign so you can just write: 2m+7 but everything else that Aaliyah has posted is on point.
October 27, 2014

math
Set this up as a system of equation then solve: x = chalk y = stapler x+2y = 10 <--- equation 1 3x+2y = 18 <---- equation 2 Now, there are many methods when solving systems of equation, but I would use substitution method for this problem. Look at the first equation: x+...
October 27, 2014

Math
Actually after reading the problem, I think I rounded wrong. 338700 should be the correct answer.
October 27, 2014

Math
Set up an equation then solve: 320000 = x - x*(.055) where x is the amount they must sell their house for minus the 5.5 interest rate and still maintain 320000 x = 338624 But it says to round to the nearest $100, so x = 338600
October 27, 2014

Physics
Whoops, I think my units are off because since k is measured in N/m I need to convert cm to m Answer should be .03 Joules
October 27, 2014

Physics
Potential Energy of the compressed string at x=3.0cm: W = (1/2)*k*x^2 where k = spring constant = 15 N/m x = distance = 3.0 cm W = (1/2)*15*3^2 W = 67.5 Total work: W_t = (1/2)*k*x^2 where x = 4+3 = 7 W_t= (1/2)*15*7^2 W_t = 367.5 W_t - W = 367.5 - 67.5 Work needed for the ...
October 27, 2014

math
For the first problem just use a calculator to convert everything into decimals. a= 3.5 b = sqrt(15) =3.87 c = sqrt(1/16) = .25 d = 26/100 = .26 It's clear after converting everything, that choice b is the greatest Numer 2: Irrational numbers are numbers that cannot be ...
October 27, 2014

Math
For everyone 1 goat, there are 4 sheep. 50*4 = 200 200 sheep
October 27, 2014

Math
Set up an equation: (1/4)x = (2/3)*60 Solve for x to get how much Peter has x = 160 160 + 60 = 220
October 27, 2014

Physcis
There's a formula for this! R = R_o * A^(1/3) R_o =1.3*10^-15 m A = nucleon number which in your case is 85 R = (1.3*10^-15)* 85^(1/3)
October 27, 2014

Math
a = (max-min)/2 d=(max+min)/2 is period given in the problem?
October 27, 2014

physics
If you want to check your answer, I got 283.19N
October 27, 2014

physics
I wish i could post a link of my FBD here, but the website won't allow any links to be posted. It's really hard to explain on here if you can't see a free body diagram. Could you show me how you started it and maybe I can try to follow what you're doing?
October 27, 2014

physics
John, first draw a free body diagram. then break each vectors up into x and y components Fx = 5.6cos75 - 3.8cos45 Fy = 5.6sin75 - 3.8sin45 Direction: tan^-1(Fy/Fx)
October 26, 2014

algebra
A(t)=3-2t^2+4^t just plug 2 in for t to get A(2) then plug 1 in for t to the given equation to get A(1) Then A(2) - A(1)
October 26, 2014

Math
Thats correct so far.
October 26, 2014

Physics
Part a) Assume that downward is positive for this problem. V=V_o + g*t V_o = 2.13 g=9.8 t=4.38 V=2.13 + (9.8*4.38) V = 45.1 m/s part b) x= V_o*t + (1/2)*g*t^2 x=(2.13*4.38)+(1/2)*9.81*4.38^2 x=103.43 note that the helicopter is going down at: x1=2.13*4.38 = 9.33 X = x - x1 X...
October 26, 2014

algebra
Wait Mr. Reiny, I think there is a typo. 3x^2+x-2=0 So there should be two roots x= -1 x = 2/3 And since the question is asking for "integer", I guess only -1 works since 2/3 is a fraction which is not an integer.
October 22, 2014

algebra
Equation: 3x^2 + 1*x = 2 I don't think that equation will factor, so you're going to have to use the quadratic formula to find what x is. 3x^2 + x - 2 = 0 I got x to be -1 and 2/3 Let me know if you got the same from applying the quadratic formula
October 22, 2014

physics
So it takes the blade .398s to move 90 degrees a full circle is 360 degrees 360/90 = 4 So time it takes to move around whole circle: T = .398*4 = 1.59s Velocity = Distance / time Distance in this case is the circumference of circle: C=2*pi*r where r is radius so C = 2*pi*(.352...
October 22, 2014

Algebra
First find the slope of the line through those coordinates. Slope formula: m = (y2-y1)/(x2-x1) m=(7-3)/(4-5) m=4/-1 m=-4 So the slope is -4 Now use the point slope formula: y-y1=m(x-x1) y-3 = -4(x-5) y-3=-4x+20 y=-4x+23 You will get the same result if you use the other ...
October 22, 2014

math
First you have to find how much each chairs cost 560/16 = 35 So each chair cost $35. 35 * 24= 840
October 22, 2014

PHYSICS
Part a) Moment of Ineria for a sphere (formula is different depending on the shape: I = (2/5)*m*r^2 I = (2/5)*14.5*.120^2 = .0835 Angular momentum = I * angular velocity .0835 * 6.15 = .51 kgm^2/s Part B) Kinetic energy = (1/2)*.0835*(6.15)^2 = 1.579 J
October 22, 2014

physics
Is that the whole question? I'm guessing to break that force up into x and y components Fx = 52.8cos18 Fy = 52.8sin18
October 22, 2014

Math - Please Help Check My Answer
The answer the student has is correct. c = -1/13 The correct answer is A The answer is negative.
October 22, 2014

physics
D = speed * time just make sure to convert your units. Give it a try!
October 22, 2014

guidance
Key word: NOT B.
October 22, 2014

Physics
oops tan^-1(368.85/190.5) = 62.68
October 21, 2014

Physics
hmm.. Vx= 220cos30 = 190.5 Vy = 110 s=-Vy*t + (1/2)*a*t^2 2800 = -110*t + (1/2)*(9.81)*t^2 use quadratic equation to solve for t t=37.6s v=g*t v=9.81 * 37.6 v=368.85 tan^-1(v/vx) tan^-1(368.85/110) = 73.39 See if that's correct..
October 21, 2014

physics
a=(vf-vi)/t vf=73.6 * (1/3600)*1609.34 = 32.9 m/s vi = 0 (at rest) a=32.9/7.68 = 4.28 m/s^2
October 21, 2014

Precalculus
a) radius of a circle a=pi*r^2 to write this as a function of r a("r")=pi*r^2 pug in what r is to find what a equals b) r(t) = 2.2t where you plug in what your t is to give you r try using what I gave you for part a and b to find out the rest. Post if you have ...
October 21, 2014

Math
weekly revenue rate = -500*1 Price decrease rate = -.45 Marginal Revenue = (-500*1)(-.45) = 225
October 21, 2014

Math
This type of problem involves a lot of trig idenities, I just looked them up.. Lets look at the LHS: csc^2(x)= 1/sin^2(x) cos^2(x) = 1-sin^2(x) Now we can say: csc^2(x)*cos^2(x) = (1-sin^2(x))/sin^2(x) now lets look at the RHS: csc^2(x) = 1/sin^2(x) and we can change that 1 to...
October 20, 2014

physics
Note that "r" and "g" cancels out when you put the coefficient of friction equal to each other for car A and car B
October 20, 2014

physics
Coefficient of friction is: u=v^2/(r*g) now lets apply this formula to the problem Set Car A = Car B and you get V_a^2/V_b^2 = u_a/u_b v_b=v_a*sqrt(u_b/u_a) (13.8)*sqrt(.843/.333) = 21.95 m/s
October 20, 2014

TYPO
Made a small typo.. Answer is y+9 =(7/8)*(x+2)
October 20, 2014

Jay
Yeah
October 20, 2014

Jay
Point slope form is y-y1 = m(x-x1) y-(-9) = (2/7)*(x-(-2)) y+9 =(2/7)*(x+2)
October 20, 2014

Algebra
You gotta make the graph, use those points.
October 20, 2014

Algebra
x coordinate can be all negative # and zero y can only be all negative # so make a t chart x=0,-1,-2,-3,-4,-5……. y=-1,-2,-3,-4,-5,-6….
October 20, 2014

physics
Was velocity given in the figure?
October 20, 2014

MISTAKE
Oops, I made a mistake.. (4500*.04)+(.1*x)=1000
October 20, 2014

algebra
Set this up as an equation. (4500*.1)+(.1*x)=1000 solve for x to get your answer.
October 20, 2014

Algebra
Well, rate of change = slope deltaY/deltX = slope deltaY = (y2-y1) deltaX =(x2-x1) For the year 1990-1992: deltaY = (55-52) = 3 deltaX =(1992-1990) = 2 3/2 = 1.5=slope So basically, you have to pick 2 years where deltaY > 3 deltaY <= 2 so the only years that meet those ...
October 18, 2014

physics
Sorry, I made an error… Vector A has both an x and y component: Fx=10cos25=9.06 Fy=10sin25=4.266 Magnitude of A = sqrt(9.06^2+4.266^2) = 10.0141 Vector B only has x components: Fx=8 Magnitude of B = 8 10.0141*8 = 80.112
October 18, 2014

physics
If I'm reading this correctly, the question wants you to find the magnitude of vector A and then multiply it to magnitude of vector B. If that's the case then… Vector A has both an x and y component: Fx=10cos25=9.06 Fy=10sin25=4.266 Magnitude of A = sqrt(9.06^2+4....
October 18, 2014

Intermediate Algebra
find the average of hours of homework completion. (6+9)/2 = 7.5 hours
October 18, 2014

Trigonometry
sin^-1(12/13) = 67.38 180-67.39 = 112.62 = A sin^-1(-7/25) = -16.26 = B Tan ( A - B) = ??? I think that's how you approach it.. someone verify please?
October 15, 2014

math
4+x+2=9
October 15, 2014

math
1/(8000*450) = 2.77*10^-7
October 15, 2014

math
Wait it's 2x+5=-c
October 15, 2014

math
I agree with your answer.
October 15, 2014

Algebra 2 (PLEASE, HELP ME!)
I think for part C: match a t chart for x and y for the light weight, x can be anything bigger than 200 and lower than 230 so x can be 200 all the way to 229 Now do the same for the heavy weight class then plot them. for part D: It's asking at what point the lines ...
October 15, 2014

algebra
Hmm.. lets start with the polynomial (x+13)(-x+12) = -x^2 - x + 156 part b) The discriminant is everything inside the square root of the quadratic formula 150= -x^2 - x + 156 -x^2-x+6 a=1 b=-1 c=6 so: b^2-4*a*c is the discriminant -1^2 - 4*-1* 6 = 25 and 25 > 0 part c) Just...
October 15, 2014

Physics
Kinetic energy + Potential Energy (1/2) *m*vf^2 + (1/2)*m*vi^2 = mgh m=mass but we we really don't need the mass to figure this problem out since we can factor it out of the equation Now isolate the vf vf = sqrt(2*g*h - vi^2) g=9.81 h=30 vi=45 vf=sqrt(2*9.81*30 - 45^2) vf=...
October 15, 2014

Math
97 rounded to nearest ten gives 100 97 rounded to nearest hundred gives 100 118 rounded to nearest ten gives 120 118 rounded to nearest hunted gives 100 5 rounds to nearest ten is 10 179 rounded to nearest ten gives 180 179 rounded to nearest hundred gives 200 5091 rounded to...
October 15, 2014

physics
if you still need this i'll take a shot at it.. I drew this a free body diagram of this You should get a triangle when you do this where 228 is your hypothenuse is 228 so the formula to to find the missing side is c^2=a^2+c^2 where c=228 and a=50 so the missing side b = ...
October 15, 2014

math
x=semir y=sarah z=sung semir sold 3 times as many meals as sarah x=3*y sung sold 2 more meals than sarah. z=2+y y=y so 3*y + y + (2+y) = meals sold you can simplify more 3y+2y+2
October 14, 2014

Math
I set up as an equation: (1/2)*x*3 = 324 solving for x will give you the total cost of the three pairs of shoes x=208 324-216 = 108 hand bag is $108
October 14, 2014

Pre-Cal
It mean's that the college of nursing students doesn't have to take statistics
October 14, 2014

physics
F=ma F=Force m=mass a=acceration F/m = a 3.25/3.8 = .855m/s^2 a=.855 m/s^2 now we have to find velocity at given time a*t=v .855*16.5 = 14.11 m/s now momentum formula p=m*v p=momentum m=mass v=velocity p=3.8*14.11 = 53.616 Ns Someone check my work.
October 14, 2014

math
Or if it's written (7 * 4) - (4/2) = 26 then its correct.. Actually, I think this post is the one you should look at
October 13, 2014

math
(7 x 4 - 4)/2 = 26 PEMDAS Do calculations in the parenthesis first: 24/2 = 26 Do you think that's true or false?
October 13, 2014

Math
C probably.
October 13, 2014

Algebra 2
should get a diagonal line
October 13, 2014

Algebra 2
Make a t chart and plug in an initial x to get your y to get your points then graph. for example: pick 1 for x as your starting y=|1|/2 - 3/4 y=-1/4 so first points are x=1 y=-1/4 x=2 y=??? x=3 y=??? so on..
October 13, 2014

Math
surface arena of a cone: A=pi*r(r+sqrt(h^2+r^2)) where r=radius Given: A= 258 cm^2 r=4 cm find h 258=(3.14*4)(4+sqrt(h^2+4^2)) 258=12.56(4+sqrt(h^2+16)) 258/12.56 = 4+sqrt(h^2+16) 16.54 = sqrt(h^2+16) square both sides 274.233 = h^2 + 16 258.233 = h^2 h=16.0696
October 13, 2014

pre cal
circumference of a circle: C=2*pi*r where r=radius=27/2=13.5ft pi=3.14 C=84.78 It's making 2 rotations every 2 seconds or in other words, 1 rotation every 1 second. note its asking for mph: 1hour=3600 12inch=1foot 1mile=5280 Formula to solve this: (n*C*3600)/(12*5280) ...
October 13, 2014

math
There are 75 employees, and they all get 2 weeks off per year, so total weeks off for everyone is: 75*2 = 150 weeks Now: 1 year = 52.18 weeks The total weeks that all 75 employees work without the 2 week vacation is: 75*52.18 = 3913.5 Total week - vacation week=net working ...
October 13, 2014

MATH 101
Can't really factor anything out of this. (7 a - 3 b) (8 a + 9 b) If you FOIL: you get 56a^2+39ab-7b^2 I just kind of did trial and error.
October 13, 2014

Math
If you tried 1 2 3 4 and took the product you would get 24 which doesn't equal one of the above numbers, so this combination wouldn't be correct.
October 13, 2014

Math
Take a look at 0,1,2,3 Those are 4 consecutive numbers. Now lets take the product of them: 0 * 1 * 2 * 3 = 0 As you can see, it's equal to one of the integers which is 0 So that meets the requirement. From those set of numbers, 3 is the largest.
October 13, 2014

Algebra
Hmm.. Let's break this down with what is given. There is a total of 1065.95 total. Mary has 122 in the cash register initially. So subtract 1065.95 - 122 = 943.95 943.95 is the total items she sold including tax Let's Figure out that amount excluding the tax, which is ...
October 13, 2014

Math
x<= 2100-300p 600 <= 2100 -300p p<= 5
October 12, 2014

Algebra 2
ah okay, well it's really basic algebra then. Just isolate the h h=(3v)/(pi*r^2)
October 12, 2014

Algebra 2
So…. what's given and what does it ask you to solve for?
October 12, 2014

Math
A = 1, otherwise the product would have 5 digits. D = 9 because A = 1. B = 0 or 1, otherwise the product would have 5 digits. If B = 1, then C = 0, otherwise the product would have 5 digits. But 1109 * 9 = 9981, which isn't right. So B = 0. Then 9*D = 9*9 = 81, so 8 + 9*C ...
October 12, 2014

sci207
LOL, this is a funny question.
October 12, 2014

Algebra
Yes. You are correct. y=3x plug 1000 into x 3 * 1000 = 3000
October 12, 2014

engineering science N4
I feel like the weight of the steel block has to be given in order to solve this problem…
October 12, 2014

maths
I set this up as a polynomial x^2-64x+960 factor this (x - 40)(x-24) where you it's roots to be 40 and 24 so 40 + 24 = 64 40 * 24 = 960
October 12, 2014

CHEMISTRY
First find molar mass of C6H12O6: I found it to be 180.1566 g/mol now find the ratio of moles 5.85/180.1566 = .0325mol Molality of C6H12O6: (.0325*1000)/255 = .127 note: the value 1000 is from the density of water which is 1.00g/mL So freezing point: delta_T = -k_f * m k_f = 1...
October 12, 2014

physics
yeah you are right, ignore my post.
October 12, 2014

physics
Final Velocity of 2.2kg ball: Vf = (V_i *(m1-m2) + (2m2*v_i2)/(m1+m2) v_i =1.27 m1=2.20 m2=7.2 v_i2 = 0 (because it was a rest initially) Vf=(1.27*(2.2-7.2)+(2*7.2*0)/(1.27+7.2)) =-6.35 For final Velocity of 2nd object: Vf = (V_i2 *(m2-m1) + (2m1*v_i/(m1+m2) Vf=(0*(7.2-2.2)+(2...
October 12, 2014

Science quick question urgent check my answer
Spores form part of the life cycles of many plants, algae, fungi and protozoa. In bacteria, spores are not part of a sexual cycle but are resistant structures used for survival under unfavourable conditions. --Wikipedia
October 1, 2014

Math
The college president asks the statistics teacher to estimate the average age of the students at their college. How large a sample is necessary? The statistics teacher decides the estimate should be accurate within half year and be 92% confident. From a previous study, the ...
September 21, 2014

math
you download 12 new songs to your mp3 player. then you delete 5 old songs.. write each amount as an integer?
August 28, 2014

Math
What do I do next after that?
August 2, 2014

Math
but i dont get the first one
August 2, 2014

Math
Simplify the following expressions by using trigonometric form and De Moivre's theorem a. (√3-i)^4 b. (-4+4i√3)^5 c.(2+3i)^4 d. (4-i)^6
August 2, 2014

algebra
A three quarter inch wire has 12 ohms resistance. How much resistance has the same length of half-inch wire, if resistance varies inversely as the square of the diameter?
May 23, 2014

English
What is a metaphor for a deep voice?
May 22, 2014

Math homework help
Check out the polar coordinate pairs that label the same point. Several pairs may be possible. A) (2, 2pi/3) B) (2, -pi/3) C) (-3, pi) D) (2, 7pi/3) E) (3,0) F) (-3,0) G) (-2, -pi/3) H) -3, 2pi)
May 17, 2014

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