Sunday

February 26, 2017
Total # Posts: 29,421

**phy**

The units of A) are acceleration, m/s^2 , not momentum which is mass * velocity so NO WAY If it reversed direction of velocity without changing sign of momentum then obviously it came back with NEGATIVE MASS ! so NO WAY C) well all right D ) LOL, it was thrown at zero speed ? ...

*November 4, 2016*

**Physics**

An object of mass 1.00kg is moving over a horizontal circular path of radius 2.00m, with a speed of 3.00ms^-1. Determine: (a) its centripetal acceleration (b) its kinetic energy (c) its period (d) its angular velocity

*November 4, 2016*

**probability**

Draw four trees with branches :) 2 of the 16 are banana with basket 2 of the 16 are AT without horn so 4/16 = 1/4 = .25

*November 3, 2016*

**Physics**

F = m a = m v^2/r = 10 so mv^2 = 10 r = 10 Ke = (1/2) mv^2 = 5 Joules

*November 3, 2016*

**Algebra**

e^x / (x^3 + 1/x^3) multiply top and bottom by x^3 x^3 e^x / (x^6 + 1)

*November 3, 2016*

**physics**

v = Vi + a t 0 = 3 + a t t = -3/a d = Vi t + (1/2) a t^2 15 = 3 t + (1/2) a t^2 15 = 3(-3/a) + (1/2) a 9/a^2 15 = -9/a + 9/2a = -9/2a 30 a = -9 a = -9/30

*November 3, 2016*

**sir damon plz help me or steve**

well, maybe V = 50 sin (2pift) and i = I sin (2pift - phi) then di/dt = 2pif I cos (2pift-phi) with your numbers 2 pi f = 200 V = 50 sin 200 t i = 20 sin (200 t-phi) di/dt = 4000cos (200 t - phi) now VL = L di/dt = L*4000 cos(200t-phi) so 4000 L = 30 L = 3/400 Vr = iR =R*20 ...

*November 3, 2016*

**Calc**

p = 2w + 2 L L = 50/w so p = 2 w + 2 (50/w) p = 2 ( w+50/w) dp/dw = 0 at min or max = 2 [ 1 - 50/w^2 ] w^2 = 50 w = 5 sqrt 2 then L = 50/[5 sqrt 2 ] = 10 srt 2/2 = 5 sqrt 2 LOL, it is square :)

*November 3, 2016*

**algebra**

You are welcome.

*November 3, 2016*

**algebra**

1/3 = 2/6 = 4/12 1/2 = 3/6 = 6/12 halfway between 4/12 and 6/12 is 5/12

*November 3, 2016*

**Physics**

but, but, it would have been fun :(

*November 3, 2016*

**Maths**

compounded three times 5% each time 4630.50 * (1.05)^3 in the second one is it compounded once or twice a year? if once 4 = (1+x)^2 2 = 1+x x = 1.00 so 100% doubles the first year, doubles again the second year.

*November 3, 2016*

**Physics**

Ac = v^2/R F = m Ac = m v^2/R but F = mu m g so mu m g = m v^2/R mu = (v^2/R)/g ratio of centripetal acceleration to gravitational acceleration :) by the way on earth g is more like 9.81 m/s^2, not 9.88

*November 2, 2016*

**physics**

This is a trick question. (a) Since there is no friction, the potential energy at the TOP (at 5 meters), m g h = 3 * 9.8 * 5 becomes ZERO AT THE BOTTOM if you define ground level as zero potential. Note the potential difference depends only on altitude. The ramp changes ...

*November 2, 2016*

**Math**

three plus 63/80 16/80 44/80

*November 2, 2016*

**Math**

if far less fun than changing them all to xxx/80 :)

*November 2, 2016*

**Chemistry**

1/2 after 10 1/4 after another 10 1/8 after a third 10 so 345/8 In general fraction left = 1/2^n where n is the number of half lives

*November 2, 2016*

**Physics**

Fx = 181 cos 20.8 normal force = m g - 181 sin 20.8 friction force =.29(mg-181 sin 20.8) ma= 181cos 20.8-.29(mg-181 sin 20.8) divide by m to get a now you do the second one the same way

*November 2, 2016*

**Physics Urgent!**

a = -mu g = -.705*9.8 = -6.91 m/s^2 v = Vi + a t 0 = 28.7 - 6.91 t t = 4.15 seconds to stop d = average speed * 4.15 = 28.7/2 * 4.15 = 59.6 meters he stops in 59.6 meters we stop in 59.6 + .427 * 28.7 meters so we better be .427*28.7 = 12.3 meters behind or we hit him just ...

*November 2, 2016*

**Physics**

a = change in v /change in time = (6.7 - 12.1)/4 = -1.35 m/s^2 F = m a = - mu m g so mu = 1.35/9.8 = .138 average speed = (12.1+6.7)/2 = 9.4 9.4*4 = 37.6 meters

*November 2, 2016*

**Math**

3 [ .035* 3800 ] = 399

*November 2, 2016*

**Math**

2 L + 2 w = 44 so L + w = 22 L w = 120 so L = 120/w 120/w + w = 22 w^2 - 22w + 120 = 0 (w-12)(w-10) = 0 ten by 12 :)

*November 2, 2016*

**math**

-4*5 = -20

*November 2, 2016*

**huh**

Unless it is a square, there is no unique answer.

*November 2, 2016*

**Math**

You are welcome :)

*November 2, 2016*

**Math**

3(8/8) + 7 /8 = 24/8+7/8 = 31/8 3 7/8

*November 2, 2016*

**still math**

You are welcome.

*November 2, 2016*

**still math**

combine like terms 3 apples + 4 grapefruits + 2 apples is 5 apples + 4 grapefruits

*November 2, 2016*

**Calculus**

-1*2 + 7*3/4

*November 2, 2016*

**math**

100 (3240 -2673) /3240

*November 2, 2016*

**Trigg county**

5280 * 2 --------- 500 * 2 10560 ------ 1000 10.560 or 10.56 feet = 1/500 of a mile :)

*November 2, 2016*

**Math**

I think you may mean: 12 a - 3 b^2 12*9 - 3 * 4^2 108 - 3 * 16 108 - 48 60

*November 2, 2016*

**statistics**

http://davidmlane.com/hyperstat/z_table.html

*November 2, 2016*

**Math7 grade**

You are welcome.

*November 2, 2016*

**Math7 grade**

15 ft * 2 in/ft = 30 in 18 ft * 2 in/ft = 36 in so area on plan = 30*36 = 1080 in^2 on the real size area = 15*18 = 270 ft^2 well to compare them change in^2 to ft^2 there are 12 in /ft so 144 in^2 per ft^2 so 1080 in^2 *1 ft^2/144 in^2 = 7.5 ft^2 or you could say 30 in = 30/...

*November 2, 2016*

**Calculus**

You do not say if the wind is coming FROM NE or going TOWARD NE In navigation, sailing, and flying we usually use the FROM convention and your NE breeze has components taking you 80/sqrt 2 south and 80 /sqrt 2 west However you never know with mathematicians

*November 2, 2016*

**phy**

The same before and after of course 1200*10+2000*27

*November 2, 2016*

**Chem**

well, you have 3 mol of H2 for every mol of N2 so your reaction is not limited by either so You have the same number of atoms of N2 on left as on right so .823/.885 = .93 of each reacted so .07 of each remains .07 * .885 = .062 Mol of N2 still there and .07 * 2.654 = .186 mol ...

*November 2, 2016*

**Calculus**

u = 5 cos 30 v = 5 sin 30 so V = 5 cos 30 i + 5 sin 30 J of course cos 30 = sqrt 3 /2 and sin 30 = 1/2 so V = (5 sqrt 3) /2 i + (5/2) j

*November 2, 2016*

**Calculus**

sqrt(36 + 64) = sqrt 100 = 10 so that vector is ten units long. If you divide each component by 10, you will get a vector of length one in that same direction so < -6/10 , -8/10 > or < -3/5 , -4/5 > by the way this is a 3,4,5 right triangle :)

*November 2, 2016*

**physics**

(a) m g h = 3 g (5) =15g at top BUT I assume you are choosing it to be ZERO at the bottom (b) (1/2)m v^2 = mgh = 15 g of course (c) v = sqrt (2 g h) v = sqrt(10 g) (c)

*November 2, 2016*

**Math**

4^2 /2 - 2^2 + 5 8 - 4 + 5 9

*November 2, 2016*

**Calculus**

As far as I know the first one is true, they differ by a constant. yes, true say f = x^2 g = x then F = (1/3) x^3 + C1 G = (1/2) x^2 + C2 integral f g dx = (1/3) x^4 + C forget the constants for now, no need F G = (1/6) x^5 like no way :)

*November 2, 2016*

**Calc**

dv/dt = a which is constant so v = c + at c is v when t = 0, v0 so v = v0 + a t dx/dt = v = v0 + a t so x = constant + v0 t + (1/2)at^2 constant is x when t = 0 or s0 x = s0 + v0 t + (1/2)at^2 (but we cheated and took physics so knew that)

*November 1, 2016*

**Geography**

g = b+40 b/g =3/7 so b =3g/7 so g = 3g/7 +40 7g/7 = 3g/7 + 40 4 g = 40*7 g = 70 b = 3*70/7 =30

*November 1, 2016*

**physics**

F = m a 5890 = (1070+2140) a a = 5890/(1070+2140) then Fjeep = 2140 a

*November 1, 2016*

**PLEASE CHECK OPERATIONS WITH FRACTIONS PART 2**

13. Kevin had 3/4 yard of string. He used 1/3 of the string for a school project. How many yards of string did he use for his project? A.5/12*** B.1/3 C.7/12 D.1/4 ============================== 1/3 * 3/4 = 1/4 I do not have time to go through all these but noticed this ...

*November 1, 2016*

**Math**

12 +14 = 26 26 * 10 = 260 260/2 = 130

*November 1, 2016*

**Bob**

I have answered this three times now.

*November 1, 2016*

**Science**

http://www.jiskha.com/display.cgi?id=1478031138

*November 1, 2016*

**Math**

1.25 * 12 = 15

*November 1, 2016*

**hellllllpppp**

23/63 as I said before 23 is a prime number. This fraction can not be simplified.

*November 1, 2016*

**Science**

http://www.jiskha.com/display.cgi?id=1478031138

*November 1, 2016*

**Maths**

2005 /4 = 501 1/4 2004/4 = 501 so -7 so 2

*November 1, 2016*

**Physics**

first 20 s slope of v = a = 2 m/s^2 v = 0 + 2 t x = (1/2)(2) t^2 at t = 20 v = 40 m/s x = 400 m from t = 20 to t = 50 v = 40 m/s a = 0 at t = 50 v = 40 new a = -40/25 x = 400 + 40(30) = 1600 from t = 50 to t = 75 v = 40 - 40/25(t-50) a = -40/25 x = 1600 +40(t-50) - 20/25(t-50...

*November 1, 2016*

**PHYSICS**

omega R = v omega = v/R = 12/1.5

*November 1, 2016*

**Maths**

would it be 295,000 or 296,000 is 3 >/= 5 ?

*November 1, 2016*

**Maths**

(1.61 + 0.81 + 1.21) /3

*November 1, 2016*

**biology - genetics Mendelian**

need biology teacher

*November 1, 2016*

**Maths**

5.4 cm * 10 km/cm = 54 km

*November 1, 2016*

**Maths**

perimeter = 2*4 + 2*3.5 = 8 + 7 = 15 meters total area = 15 * 2 = 30 m^2 now subtract 2 and 1 = 3 so 27 m^2 27*3 = 81 dollars But not really if you ever did wall paper :) It never comes out like that perfectly, has to be lined up and edged perfectly so needs extra.

*November 1, 2016*

**Math**

-12 + n = -35 n = -35 + 12 n = - 23

*November 1, 2016*

**Maths**

sum = 180 = 2*90 two

*November 1, 2016*

**math**

2*8 = 16 16+5 = 21 so 21/8

*November 1, 2016*

**Maths**

10/10 - 7/10 = 3/10 2 Liters? that is 2,000 mL 3/10 (2,000) = 600 mL

*November 1, 2016*

**Maths**

1000/200 = 5 5 * 40 = 200

*November 1, 2016*

**Math**

7/8 - 3/4 is 7/8 - 6/8 = 1/8

*November 1, 2016*

**math**

what can you divide 23 by? Nada ! Prime the end 23/63

*November 1, 2016*

**math**

time starting at 2007 t n 0 35250 5 28200 7 ? n = m t + 35250 28200 = m (5) + 35250 5 m = - 7050 m = -1410 so n = -1410 t + 35250 if t = 7 years n = -1410 (7) + 3520

*November 1, 2016*

**geography**

Rivers ! Harbors ! Paths through deserts and mountain ranges!

*November 1, 2016*

**science plz correct me**

A. I thought I told you, more MASS

*November 1, 2016*

**AP Statistics**

I do not know what you did in unit but find mean and median for women and for men for example median women 21 26 26 30 31 33 33 34 34 35 37 38 41 41 41 42 49 61 72 74 80 There are 21 10, median, 10 10 smaller than 37 and 10 bigger median is 37 now do it for men is it higher?

*November 1, 2016*

**science**

E = i R 21 = 3 R R = 7 Ohms

*November 1, 2016*

**Science 7**

No! Read carefully, more MASS

*November 1, 2016*

**Science 7**

G M1 M2 / d^2 bigger mass, same d ---> bigger force

*November 1, 2016*

**Calculus**

well, x^2 +y^2 = 49/4 put that back in 2 (49/4)^2 = 49 (x^2-y^2) 49/8 = x^2 - y^2 49/4 = x^2 + y^2 2 x^2 = 3*49/8 well that is two points x values :) you have 2 y values for each x so 4

*November 1, 2016*

**Calculus**

find where dy/dx = 0 4 (x^2 + y^2)(2x + 2 y dy/dx) = 49 (2 x - 2 y dy/dx) when dy/dx = 0 4(x^2+y^2)(2x) = 49(2x) x^2+y^2 = 49/4 = r^2 it is a circle center at (0,0) , r = 7/2

*November 1, 2016*

**Pre-algebra**

74 is an integer 74/1 Now if you had said 7.4 I would have said 74/10 so still rational

*November 1, 2016*

**Pre-algebra**

1/1 2/2 4/2 or 4/1 in fact since every integer is divisible by one every integer is a rational number. You have to get far out to get irrational, like sqrt( 2 ) or pi or e Remember that fractions are generally ratios of whole numbers so rational like 3/273 is rational

*November 1, 2016*

**Science 7**

I guess if the switch is closed the bulb is on. yes G M/r^2 but we are assuming comparable radii

*November 1, 2016*

**Math-Check my answer**

3 a - 4 </= 5 3 a </= 9 a </= 3 yes

*November 1, 2016*

**math plz help**

LOL - I suppose it could be 7.5 but it said the GREATEST common factor well if they were 30 oz, we would not get 15 so it looks like 15 is the biggest that will go into all three 15 --> one ball 30 --> two balls 60 --> four balls

*November 1, 2016*

**Algebra**

well, I would multiply both sides by 15 x 15 x (2/15) = 15 x (13/x or 2 x = 15 * 13 x = 7.5 * 13 x = 97. 5 indeed Now some may say just cross multiply well ok 2 x = 15 * 13 immediately. but I do not like the words "cross multiply" despite the fact that they are ...

*November 1, 2016*

**science**

No way I am going to just say a heat wave is hot. What answers would you give if we were not around?

*November 1, 2016*

**physics**

I wonder if the cabinet is accelerating down call it a ma = mg - T m(9.81-a) = 2390 T - .68 * 193 *9.81 = 193 a or 193 a = 2390 - 1287 a = 5.71 m/s^2 (dangerous) m (9.81-5.71) = 2390 m = 583 kg

*November 1, 2016*

**Chemistry help emergency? (theoretical mass/mol)**

You do not have enough of one or the other, limiting the amount of Cu resulting. Use the one you do not have enough of. Your mols of Al must be at least 2/3 the number of mols of CuCl....... If it is less use it. If it is more use the CuCl ... and you will have some Al left over

*November 1, 2016*

**Maths (really hard)**

what is length AB? sqrt(4+ 64) = sqrt 68 = 2 sqrt 17 so length AC = sqrt 17 what is slope AC? It is -1/slope AB slope AB = -2/8 = -1/4 so slope AC = 4 now point C (x,y) Oh, wow, problem over go right one from A go up 4 from there what is hypotenuse? LOL sqrt 17 !!!! so x = 1...

*November 1, 2016*

**Maths (done question a but cant do b)**

-2 + -3 = -5 -5/2 = -2.5 which is y of C 4 ) 6 = 10 10/5 = 5 which is x of C so C(5, -2.5) now AC dx = 5-4 = 1 dy = -2.5 - -3 = .5 d^2 = 1+.25 now CB dx = 6 -5 = 1 dy = -2 - -2.5 = .5 d^2 = 1 + .25 the same

*November 1, 2016*

**LOL - so what is C (?,?)**

Do I have to do part a too ?

*November 1, 2016*

**maths**

change in y = 6 - (-3) = 9 change in x = 7 -4 = 3 so d = sqrt (81 + 9) = sqrt (90) = 3 sqrt 10

*November 1, 2016*

**Math**

You are welcome.

*November 1, 2016*

**Math**

85% = 85/100 = 0.85

*November 1, 2016*

**Calculus**

You are welcome.

*November 1, 2016*

**Calculus**

Sometimes conventional obscurity is insufficient and extraordinary efforts must be made to confuse the student. One seemingly simple but surprisingly effective technique is to reverse the usual roles of x and y.

*November 1, 2016*

**Calculus**

yes it is. Perhaps you are misled by the x being the independent variable instead of y When y = 1 x = 1^3 = 9 (1)^2 + 5 = 1 - 9 + 5 = -3 sure enough now the problem dx/dx = 1 = 3 y^2 dy/dx - 18y dy/dx 1 = (3y^2-18y)dy/dx dy/dx = 1/ (3*1^2 -18*1) dy/dx = 1/(-15) = -1/15 amazing...

*November 1, 2016*

**Science**

well, probably there was air and water in it and the air expanded in the heat pushing the water out.

*October 31, 2016*

**Math**

4 * 7 * 25 = 100 * 7 = 700

*October 31, 2016*

**chemistry**

pentaamminesulfatocobalt (III) bromide http://seattlecentral.edu/faculty/dwick/CC%20name.pdf 1L is the one, NH3 and SO4 reversed

*October 31, 2016*

**Physics**

I am going to assume a flat and earth and the sun at infinity :) In that case the tip of the hawk's shadow is directly under the hawk and moves at the hawk's horizontal speed. u = 6.09 cos 78.6

*October 31, 2016*