Friday

February 12, 2016
Total # Posts: 25,219

**physics**

m v^2/r = .7 m g or Ac = .7 g :) 39^2 / r = .7 (9.81) r = 39^2/ (.7*9.81)
*December 18, 2015*

**PHYSICS**

v = Vi + a t v = 0 when it stops 0 = 2.7 - .12 t y = 2.25 seconds to stop d = Vi t - (1/2) a t^2 = 2.7 * 2.25 - .5 * .12 * 2.25^2
*December 18, 2015*

**Physics**

friction force up slope = mu m g cos 30 work done by friction = -80 mu m g cos 30 drop in height = 80 sin 30 = 40 ft potential energy drop = m g (40 ft) ke = (1/2) m v^2 so (1/2)m(45)^2 = 40 m g - 80 mu m g cos 30 1012 = 40(32) - mu * 32 * 69.3 1012 = 1280 - 2218 mu mu = (1288...
*December 18, 2015*

**Random answers**

Hey, try the problems. also be careful typing y-5/3=1 which is y = 8/3 is NOT (y-5)/3 = 1 which is y = 8
*December 18, 2015*

**Math**

0.9 * 59.99 = 53.99 5 * .035 * 660 = 115.50 agree
*December 18, 2015*

**English**

I agree with all four answers.
*December 18, 2015*

**One more for Damon!**

buy the pizza first 21.39 - 12.99 = 8.40 for the water 8.40/2.10 = 4 bottles or A
*December 18, 2015*

**Math**

2. 1y+1.2 y = 2.2 y so 2.2 y + 1.2 d 5. -3m + 3m + 18 = 0 + 18
*December 18, 2015*

**Math**

Hey, you asked for the average speed but you answered 8 8 is the speed OUTBOUND 24 km/3 hours = 8 8 is the speed out, not the average speed
*December 18, 2015*

**Math**

return trip took 4 hours at 6 km/h so d = 24 km (that must be to Guam from the harbor entrance buoy :) total round trip took 3+4 = 7 hours total distance = 24+24 = 48 km average speed = 48 km/7 h = 6.85 km/h
*December 18, 2015*

**Math**

Just put a 5 where I had a ? mark :) say distance d a to b time = 3 = d/v b to a time = 5 = d/(v-15) so d = 3 v and d = 5(v-15) 3 v = 5 v - 75 2 v = 75 v = 37.5
*December 18, 2015*

**Math**

outbound at speed v back at speed (v-15) say distance d a to b time = 3 = d/v b to a time = ? = d/(v-15) You did not give me all the information
*December 18, 2015*

**Math**

2.3960 = 2.3 + 0.096 + 0.0000 2.3965 = 2.3 + 0.096 + 0.0005 the 0.0005 wins in fact you would round the second one to 2.397 :) but even 2.3961 would be a winner
*December 18, 2015*

**Math (2 Part Question)**

12 d = 25 + 8 d 4 d = 25 d = 25/4 = 6 1/4 so if more than 6 days (7 or more) ==================== check how much for 6 days? without = 72 with = 25 + 48 = 73, so no pass how much for 7 days without = 84 with = 25 + 56 = 81, so yes, for 7 days cheaper with pass
*December 18, 2015*

**Math I'm DYING!!!**

You are welcome.
*December 18, 2015*

**Hey, careful !**

Need parentheses if complex numerator Perhaps you mean (y-5)/3 = 1 multiply both sides by 3 y-5 = 1*3 = 3 add 5 to both sides y -5 + 5 = 3+5 y = 8
*December 18, 2015*

**Math I'm DYING!!!**

-21 a + 16 a factor a out a (-21 + 16) a (-5) or -5a
*December 18, 2015*

**Math I'm DYING!!!**

1. y - 5/3 =1 you want to get y alone try adding 5/3 to both sides y - 5/3 = 1 +5/3 = +5/3 ---------------- add y -5/3 +5/3 = 1 + 5/3 so y = 1 + 5/3 we need a common denominator, 4 y = 3/3 + 5/3 or y = 8/3 which is 2 2/3 ===========================now check if y = 8/3 then y...
*December 18, 2015*

**sin^-1(4/5)**

well I agree with anonymous :)
*December 18, 2015*

**Maths trigonomentry**

3 cos x = 5-4 sin x 9 cos^2 x = 25 - 40 sin x + 16 sin^2 x 9 (1 -sin^2x) = 16 sin^2 x -40 sin x + 25 9 - 9 sin^2 x = 16 sin^2 x -40 sin x + 25 0 = 25 sin^2 x - 40 sin x + 16 let z = sin x 25 z^2 - 40 z + 16 = 0 (5 z - 4)(5 z - 4) = 0 wow, that was lucky sin x = 4/5 :)
*December 18, 2015*

**Maths deduce!damon or steve plz help any one**

(p-q)^2 = p^2 - 2 pq + q^2 (q-r)^2 = q^2 - 2 qr + r^2 (r-p)^2 = r^2 - 2 rp + p^2 ---------------------------add them 2 p^2 + 2 r^2+ 2 q^2 - 2(pq+qr+rp) = 2[ p^2 + r^2+ q^2 -(pq+qr+rp)] well all those squared quantities are positive so that quantity is > (pq+qr+rp)]
*December 18, 2015*

**not my thing**

sorry I suspect you have already tried expanding all that out
*December 18, 2015*

**Social Studies**

I said that partly because he established a seaport for Russia opening to the rest of Northern Europe. It was named for him for most of the history since.
*December 18, 2015*

**Social Studies**

I have to agree, but would say Navy :)
*December 18, 2015*

**Social Studies**

(or at least Magellan's crew )
*December 18, 2015*

**Social Studies**

I think B because circumnavigation is not an advance in technology.
*December 18, 2015*

**exploration or exploitation ?**

Circumnavigation is not a technology advance but an accomplishment by Ferdinand Magellan.
*December 18, 2015*

**Math help plz?**

if 3x+1 = 4 then x = 1 when x = -3, 3x+1 = -8 I have no idea, sorry
*December 18, 2015*

**Math help plz?**

I see, your graph is on a number line
*December 18, 2015*

**do not do magic**

I have no idea what your two redlines look like Please give me two points on each line (X1,Y1) , (X2,Y2) or a slope and an intercept or something.
*December 18, 2015*

**ok, here you go**

ok x = [ -8+/- sqrt (64-16m) ]/8 so (1/8) * 2 * sqrt (64-16 m) = 3 sqrt (64 - 16 m) = 12 64 - 16 m = 144 16 m = 80 m = 5
*December 18, 2015*

**Huh ?**

differs from what by 3 ? do you mean the roots differ by 3 or something?
*December 18, 2015*

**phsice**

k x = m g sin 32.5 the frequency has nothing to do with gravity or its direction. The stretching and motion and spring force is all parallel to the slope and the gravitational force component is just constant m g sin theta. omega = sqrt (k/m) as usual
*December 18, 2015*

**history**

Since Kofi Annan is an MIT graduate, he is first in line :) However there have been thousands of mediators on thousands of subjects over the years. Recently two Presidents of the US, Bill Clinton and Jimmy Carter have served as mediators getting agreements, albeit temporary, ...
*December 18, 2015*

**Algebra 2**

Well, I do not know what the parabola has to do with this. We are asked the distance from (-2,3) to (-1, -9/4) and from that same point (-2,3) to the horizontal line y = -7/4 The second part is trivial -7/4 to 3 is 12/4 + 7/4 = 19/4 we will actually have to do the first ...
*December 18, 2015*

**Physics**

.98 kg of water is .98 *10^-3 m^3 of volume mass of zinc = z mass of copper = (4.9-z) volume of zinc = z * 2.5*10^-3 m^3 volume of copper = (4.9-z)* 19.6*10^-3 m^3 so z*2.5*10^-3+(4.9-z)*19.6*10^-3 =.98*10^-3
*December 18, 2015*

**Math**

16. Find the final balance in an account with $660 invested at 3.5% annual simple interest for five years. a) $23.10 b) $115.50 c) $683.10 <------------------- d) $775.5 ================================== 660 * .035 = 23.10 per year *5 = 115.5 + 660 = 775.50
*December 18, 2015*

**Math**

7. 77 is what percent of 192? a) x/100 = 77/192; 4.01% <---------- b) x/100 = 77/192; 40.01% c) x/77 = 100/192; 77.3% d) x/100 = 192/77; 249.4% ================================ 77(100)/192 = 40.01
*December 18, 2015*

**Physics**

initial Ke = (1/2) m * 5.4^2 energy lost to friction = 0.1 * m g * 3.50 final ke = initial ke - lost energy (1/2) m v^2 = (1/2) m * 5.4^2 - 0.1 * m g * 3.50 solve for v note that the mass cancels
*December 17, 2015*

**Math**

584/421 = 1.387 which is a 38.7 % increase another way 584 - 421 = 163 163/421 = .387 so 38.7% increase Both ways are actually the same but different ways of thinking about it :)
*December 17, 2015*

**Algraba**

.07 * 25
*December 17, 2015*

**Physics**

How high? Draw it. h = L - L cos 33.6 = L(1-cos33.6) = 3(1-.833) = .501 meters up Potential energy increase = m g h = 25 (9.81) (.501) Ke = (1/2)(25) v^2 = 25(9.81)(.501) cancel the mass and solve for v = sqrt(2 g h) as usual :)
*December 17, 2015*

**Physics!**

He is at 10 meters and must jump with an initial velocity up of 5 m/s ow long until he reaches 0 meters (ground) h = Hi + Vi t - 4.9 t^2 0 = 10 + 5 t - 4.9 t^2 or 4.9 t^2 - 5 t - 10 = 0 solve quadratic for time in the air, t in seconds now the truck has to be t seconds away ...
*December 17, 2015*

**english**

as well as with
*December 17, 2015*

**Algebra 1**

or to say it better there is an infinite number of solutions. For any real x there is a real y on the line.
*December 17, 2015*

**Algebra 1**

I guess you mean y - 4 x = 1 and y - 4 x = 1 Those two lines are quite similar, in fact they intersect everywhere and there is no single point where they intersect. This is a trick problem and there is no solution.
*December 17, 2015*

**huh?**

Perhaps you copied and pasted here. That does not work on this site.
*December 17, 2015*

**science**

1 It is just a turning block.
*December 17, 2015*

**math**

if it has to be the same variable on both sides try something like: 7x + 1 = 3x + 5 + 4x -4 in other words 0 x = 0
*December 17, 2015*

**math help plz?**

You are welcome.
*December 17, 2015*

**math help plz?**

Yes, must grow more than 9 to be more than 70
*December 17, 2015*

**Math**

You are welcome.
*December 17, 2015*

**Math**

f + f+3 = 19 or 2F + 3 = 19 74 + w -6 = 3 w or 74+w = 3w+6 that means 2w=74-6 = 68 or w = 34 90-5 = 2c 85 = 2c c = 42.5
*December 17, 2015*

**math**

16 marbles 1. independent red * blue = 4/16 * 7/16 2. dependent red then blue = 4/16 * 7/15 3.in number two the probability of blue is impacted by the fact that you have taken a marble out. The two draws are not independent on problem 2
*December 17, 2015*

**Math GP typos**

Please check what you wrote what is a and what is r in a + a r + a r^2 + a r^3 ......
*December 17, 2015*

**algebra 2**

@@@@@@@@__x^2__+3x__-2_______________ x^2 + 1 | x^4 +3x^3-1x^2+5x-3 @@@@@@@@@ x^4 +0x^3+1x^2 @@@@@@@@@-------------------- @@@@@@@@@@@@@@ 3x^3-2x^2+5x-3 @@@@@@@@@@@@@@ 3x^3+0x^2+3x @@@@@@@@@@@@@@ --------------- @@@@@@@@@@@@@@@@@@@ -2x^2+2x-3 @@@@@@@@@@@@@@@@@@@ -2x^2+0x-2...
*December 17, 2015*

**Math dump**

First: We can not see the figure so can not help. Second: I see no attempt by you to do the work. I already took the subject and do not need practice. If you are having a specific difficulty, describe your attempt to surmount it.
*December 17, 2015*

**Math**

but they each play twice so double it
*December 16, 2015*

**geometry**

As far as I know the third side could be anything between 3 feet and 13 feet. 8-5 to 8+5 You need to know more about the triangle.
*December 16, 2015*

**Social Studies**

Yes
*December 16, 2015*

**chemistry, physics**

Joules in = spec heat * m * delta T so specific heat = joules/ ( m delta T) The more accurate delta T, the more accurate the resulting specific heat if you are off one degree in ten you have a 10 % error if you are off one degree in 100, you have a 1 % error
*December 16, 2015*

**Easy Math**

she mixed this 3/4 cup of sugar up with some other ingredients in a big mixing bowl. Then she baked and divided the bowl contents up into 12 brownies
*December 16, 2015*

**Easy Math**

(3/4) / 12 = 3/(4*12) = 1/(4*4) = 1/16
*December 16, 2015*

**Math**

-10 - 16 = -26
*December 16, 2015*

**math**

we can get more careful working with each column 8 in the ones column is fine but 24*10 = 20*10 + 4*10 = 2*100 + 4*10 so 4 in the ten column and add 2 over to the hundred column 12*100 + 2 * 100 = 14*100 = 10*100 + 4*100 = 1000 + 400 so I have 1 in the thousands 4 in the ...
*December 16, 2015*

**math**

300 * 4 = 1200 60 * 4 = 240 2 * 4 = 8 then add 1200 + 240 + 8 = 1448 this uses the distributive property 362 = 3*100 + 6 * 10 + 2 4 * 362 = 4 (3*100 + 6 * 10 + 2) = 12*100 + 24*10 + 8
*December 16, 2015*

**math**

h^2 + 35^2 = 50^2
*December 16, 2015*

**Physics**

old bear solution http://www.jiskha.com/display.cgi?id=1229011401
*December 16, 2015*

**Phsics dump**

again
*December 16, 2015*

**PHYSICS getting tired of homework dump**

enough already
*December 16, 2015*

**PHYSICS - method again !**

look at: http://www.jiskha.com/display.cgi?id=1338312530
*December 16, 2015*

**physics homework dumping**

Now wait a minute, I already took this subject in 1954. I do not need practice. If you need help that is one thing but I see no sign of your attempts.
*December 16, 2015*

**physics**

time in air = 166/26 = 6.38 s so what stays up that long? well, it spends half that time going up t = 3.19 s upward v = Vi - g t at top v = 0 0 = Vi - 9.81(3.19) Vi = 31.3 m/s initial speed up
*December 16, 2015*

**physics**

F = - .59 * m g so a = - .59 g v = Vi + a t v = 16.5 - .59 (1.35)
*December 16, 2015*

**ignore what I did**

I did not understand your question.
*December 16, 2015*

**ALGEBRa 2**

2 x^3 - 4 x^2 + 5 x + 2 = 0 ?????? I suspect a typo and you do not say what you want. I assume roots. using http://www.mathportal.org/calculators/polynomials-solvers/polynomial-roots-calculator.php x1=−0.31075 x2=1.15537+1.37229∗i x3=1.15537−1.37229∗i
*December 16, 2015*

**physics**

find friction force -.66 * m g = -.66 * m * 9.81 = -6.47 m (so slows down at .66 g but forget I said that) a = F/m = -6.47 m/s^2 v = 19 - 6.47 t at t = 1.31 v = 19 - 6.47(1.31) = 10.5 m/s
*December 16, 2015*

**physics**

a = Ai e^-kt da/dt = -kAi e^-kt 518 = -k e^-7k 156 = -k e^-17k 518/156 = e^-7k / e^-17k = e^10k ln 3.32 = 10 k 1.2 = 10 k k = .12 I guess you can take it from there
*December 16, 2015*

**using elimination**

3 x + y = 0 3 x + 2 y = 6 --------------- -y = -6 so y = 6 then x = y/-3 = -2
*December 16, 2015*

**algebra**

use -3x for y (It is called "substitution") 3 x + 2 (-3x) = 6 3x - 6 x = 6 -3 x = 6 x = -2 y = -3x = 6
*December 16, 2015*

**Math**

x is the same for both points graph that, vertical line slope undefined
*December 16, 2015*

**physics**

look at http://www.jiskha.com/display.cgi?id=1338312530
*December 16, 2015*

**Physics Sound Waves**

If the listener does not move Doppler: Fl = { v/(v+vs) ] Fs Fl is frequency heard Fs is source frequency vs = speed of source AWAY from listener v = speed of sound here: when it is coming at you FL = [345/(345-vs) ] 450 going awy: Fl = [ 345/(345+vs) ] 450 so 22= 345*450 / [1...
*December 16, 2015*

**physics**

normal force = m g cos 21.8 max friction force down ramp = .17 m g cos 21.8 gravity force down ramp = m g sin 21.8 so total force down ramp = m g (.17 cos 21.8 + sin 21.8) work done by friction and against gravity sliding up a distance d = d m g (.17 cos 21.8 + sin 21.8) that ...
*December 16, 2015*

**Math**

yes, but where is it zero? function is horizontal when -8x^3+6x = 0 that happens when x (-8 x^2 + 6) = 0 x (-4x^2 + 3) = 0 x = 0 or x^2 = 3/4 x = + or - (1/2)sqrt (3) -------------------- now what is second derivative at those points? d^2y/dx^2 = -24 x^2 + 6 when x = 0, that ...
*December 16, 2015*

**math**

well, I am sorry but I just plain have to use algebra had n at the start sold 24 so have n-24 at noon sold 2/7 of (n-24) and have n/2 so n -24 - (2/7)(n-24) = n/2 14 n - 336 - 4 n + 96 = 7 n 3 n = 240 n = 80 ---------------------------- check n = 80 sold 24 so have 56 sold (2/...
*December 16, 2015*

**Physics**

What pathetic pullers! You do not say derees to what. I will assume to the x axis and not to north. x components: 16 cos 64 + 15 cos 136 + 12 cos 195 7.01 - 10.79 - 11.59 = -15.3 y components: 16 sin 64 + 15 sin 136 + 12 sin 195 = 21.7 magnitude = sqrt (21.7^2 + 15.3^2) ...
*December 16, 2015*

**math app**

u+c = 20 u-c = 6 ------------subtract
*December 16, 2015*

**La**

a = 5 r = -3 an = a r^(n-1) which is the very definition of a geometric sequence :)
*December 16, 2015*

**Physics**

LOL F = G Me m/r^2 F/m = G Me/r^2 = 9.8 F/Me = G m/r^2 = 9.8 (m/Me) so 9.8 (44/5.98*10^24)
*December 16, 2015*

**S.s**

Staying out of this! (from New England)
*December 16, 2015*

**Social Studies**

That would have been my guess.
*December 16, 2015*

**Social Studies**

Am I allowed to guess ? :)
*December 16, 2015*

**Physics**

Well, of course if you happen to be a spear fisherman who spears fish from above the water, you need to correct for refraction at the surface. More commonly, if you wear glasses or use binoculars or a telescope or a microscope, lenses work by the diffraction of light at the ...
*December 16, 2015*

**Physics**

work done by tugboat = 6000 * 4000 = 24 * 10^6 Joules work done by water = -500*4000 = -2*10^6 Joules (negative because force is opposite to motion) net work done on ship = 22*10^6 Joules Note unbalanced force on ship leads to acceleration but we do not care. a Joule is a ...
*December 16, 2015*

**Math**

You are welcome.
*December 16, 2015*

**Math**

Yes, you got it.
*December 16, 2015*

**Math**

45/33 = 1.3636363636363636363636.....
*December 16, 2015*

**Lowndes High School**

perhaps there was a drawing to go with this, for example with two congruent angles and a congruent side between them ?
*December 16, 2015*

**Math**

You are welcome.
*December 16, 2015*