Friday

January 20, 2017
Total # Posts: 28,803

**physics**

1000 * 9.81 * Vol = 25-15 = 10 N so Vol is about .001 m^3 25/.001 = 25,000 N/m^3 or about 2500 kg/m^3 or about 2.5 times that of water

*September 19, 2016*

**Physics**

h = 20 t - 4.9 t^2 15 = 20 t -4.9 t^2 4.9 t^2 -20 t + 15 = 0 solve quadratic for two values of t little t on the way up big t on the way down

*September 18, 2016*

**Physics**

acceleration F = m A dF/dt = m dA/dt (unless the mass changes:)

*September 18, 2016*

**Maths**

2 km + (3/8)j + (1/2)j = 1 j 2km = (8/8 - 4/8 - 3/8)j 2 km = j/8 j = 16 km total you do the rest now :)

*September 18, 2016*

**Math**

n + n+1 = 2n + 1 2n is even the next one is odd :)

*September 18, 2016*

**Math**

.41 L + .21 (8-L)= 2.08 .41 L + 1.68 - .21 L = 2.08 .20 L = .40 L = 2 p = 8-L = 6

*September 18, 2016*

**Math**

x-4 + x-2 + x + x+2 + x+4 = 50 5 x = 50 x = 10

*September 18, 2016*

**Math**

n-2 + n + n+2 = 3 n which you can divide by 3 :) It does not matter that they are odd

*September 18, 2016*

**Use parentheses**

I do not know what you mean x^3 + 1/(1/x^3) or what you said which is x^3 + 1 + 1/x^3 ???? if the first multiply top and bottom of second term by x^3 x^3 + x^3/1 = 2x^3

*September 18, 2016*

**whoops, go with Reiny**

I missed that this is a binomial distribution problem. The combinations are not equally likely.

*September 18, 2016*

**Math**

easier grid for me h -> 0 1 2 3 4 t -> 4 3 2 1 0 I see five possible outcomes of which 2 work so I get 2/5 HHTT is the same here as TTHH or HTTH

*September 18, 2016*

**Physical Science**

work = force * distance in direction of force 310 = force * 1.5 force = 310 J/1.5 m = 207 Newtons

*September 18, 2016*

**Math**

10 a + 5 s = 1700 so s = 340 - 2 a s+a = 270 340 - 2a + a = 270 a = 340-270 a = 70

*September 18, 2016*

**Physics**

v = a t = 2.46 t x = -10 + (1.23) t^2

*September 18, 2016*

**Math**

15 + .25 t = 20 +.05 t .20 t = 5 t = 25

*September 18, 2016*

**science**

4*12+10 = 58 grams/mol 14.17/58 = .244 mol 2C4H10 + 13 O2 ---> 10H2O + 8 CO2 mols CO2 produced = .244(8/2)=.977 mol 2*12+16 = 40 grams/mol 40 g/mol * .977 mol = 39.1 grams

*September 18, 2016*

**Math**

t = 4 c t+c = 360 5 c= 360 c = 72 t = 288

*September 18, 2016*

**calculus and chemistry**

T = Ts + (To-Ts)e^-(kt) Ts = T surrounding = 10 To = initial T = 160 60 = 10 +(150)e^-(5k) e^-(5k) = .333333 -5k = -1.1 k = .22 so 20 = 10 + 150 e^-.22t e^-.22 t = .0666666 .22t = 2.71 t = 12.3 min 12.3 - 5 = 7.3 min more

*September 18, 2016*

**Maths**

r = triangle leg = 20 so is the base 20 so equilateral so 60/360 = 1/6 of circle (1/6)2 pi r =(1/3)pi 20 = 20.94 cm

*September 18, 2016*

**Physics**

work done = loss of ke = (1/2)m v^2 = 1000*625 Joules power = work/second = 1000 * 625 / 5 Watts

*September 18, 2016*

**Integrated Math**

correct

*September 18, 2016*

**messed up link**

http://en.wikipedia.org/wiki/Galileo%27s_Leaning_Tower_of_Pisa_experiment

*September 18, 2016*

**physics**

The weight does not matter (Google Galileo, http://en.wikipedia.org/wiki/Galileo%27s_Leaning_Tower_of_Pisa_experiment) about 9.81 m/s^2

*September 18, 2016*

**scince**

10 log base ten of power ratio or in this case 10 log 20 about 13 dB If by "intensity" the question means amplitude rather than power then it is 20 log or about 26 dB

*September 18, 2016*

**Physics**

http://www.bbc.com/news/business-27021610

*September 17, 2016*

**Physics**

a = change in velocity/change in time = (-10 - 10)/5 = -20/5 = -4 m/s^2 v = vi + a t at t = 2 v = 10 -4*2 = 2 m/s at t = 3 v = 10 -4*3 = -2 m/s

*September 17, 2016*

**PRE-CAL**

yes, about 55 years 10% doubles in about 7 years :)

*September 17, 2016*

**Physics (Mechanics)**

straight up I guess (1/2) m v^2 = m g h h = 22^2/(2*9.81) total height = .8 + h

*September 17, 2016*

**physics**

m g h = 5.2 * 9.81 * 3.1 Joules

*September 17, 2016*

**physics**

(12)(15)(8.7)^2

*September 17, 2016*

**physics**

m g h

*September 17, 2016*

**physics**

W = F d 307 = F (1.1)

*September 17, 2016*

**Science**

500 *4 = fulcrum force * 1.5 fulcrum force = 500 *4/1.5 force up = fulcrum force force down = 500 + bolt force- so bolt force = fulcrum force - 500

*September 17, 2016*

**linear programming**

Oh, forgot the y<8 constraint

*September 16, 2016*

**I did one yesterday**

I did one of these for him yesterday.

*September 16, 2016*

**HISTORY**

Meanwhile I am wondering if the slaves bought one way or round trip tickets.

*September 16, 2016*

**What are your answers ?**

I bet you can get some of these if you really try. Post your answers and if you are wrong I suspect you will hear about it.

*September 16, 2016*

**Social Studies**

I disagree.

*September 16, 2016*

**linear programming**

well do it. graph the two lines in the first quadrant. y = -(5/9)x + 10 must be above and right points (0,10) and (18,0) y = -(9/8)x + 18 must be below and left points (0,18) and (16,0) intersection at (72*8/41 , -64*5/41 + 10) which is about (14,2) at 0,18 --> 126 at (14,2...

*September 16, 2016*

**Math**

8 (50 +4) = 8*50 + 8*4 = 400 + 32 = 432

*September 15, 2016*

**Math, number and operations base**

8*1000 + 5*100 + 17*10 + 12 *1 = 8*1000 + 5*100 + 1*100 +7 *10 + 1*10 + 2 = 8*000 + 6*100 +8*10 + 2 = 8682 agree :)

*September 15, 2016*

**Please help with Algebra 2 Ms. Sue**

sure, why not slope AB = -2/-6 = 1/3 slope AC = -8/-4 = 2 slope BC = -6/2 = - 3 oh! AB is perpendicular to BC ! slope AB = -1/slope BC

*September 15, 2016*

**maths need help**

http://www.wolframalpha.com/input/?i=derivative+x%5E(e%5E3x)%5Ex+

*September 15, 2016*

**need to know takeoff speed**

Then use conservation of momentum

*September 15, 2016*

**Linear Algebra**

let A be on x axis = a i + 0 j then B put on y axis = 0 i + b j (b could be - of course) ||A + cB|| = || sqrt(a^2 + c^2b^2 || which is >/= sqrt a^2

*September 15, 2016*

**physics**

t = time = distance/speed = 15.2/41.3 drop = (1/2)g t^2 = 4.9 t^2

*September 14, 2016*

**Physics**

c = 3*10*8 m/s seconds/yr =3600 s/h * 24h/day * 365days/yr

*September 14, 2016*

**algebra**

2 x + 4 x + 5 x = 44 11 x = 44 x = 4 2 x = 8 etc

*September 14, 2016*

**TYPO**

b/g = 3/4 now 3 boys/7 total is again 3 boys/4 girls the schools have the same number of girls, boys and totals.

*September 14, 2016*

**Math**

b/g = 3/4 now 3 boys/7 girls is again 3 boys/4 girls the schools have the same number of girls, boys and totals.

*September 14, 2016*

**math**

7/1 5/2 8/10

*September 14, 2016*

**Geometry**

You are welcome.

*September 12, 2016*

**Geometry**

http://www.jiskha.com/display.cgi?id=1473719167#1473719167.1473720184

*September 12, 2016*

**Geometry**

I did it. Check down two

*September 12, 2016*

**science**

and snow and ice melt

*September 12, 2016*

**Geometry again**

look below

*September 12, 2016*

**geometry**

I guess the base is 3x and both sides are 2x or the base is 2x and both sides are 3x so 3x + 4x = 112 or 2x + 6x = 112 x = 112/7 = 16 and 3x = 3*16 or x = 112/8 = 14 and 2x = 2*14

*September 12, 2016*

**History**

On second thought, do not check below :)

*September 12, 2016*

**History**

Maryland, Virginia, Pennsylvania all very different charter arrangements, especially religions. Look at answers below maybe.

*September 12, 2016*

**Calculus**

I guess maybe you mean the average value of the function in that domain. integral = (3/4)x^4-4x^3 at -5 = (3/4)625-4(-125) = 968.75 at 4 = (3)64-4(64) = -64 so I get 968.75 + 64 = 1032.75 divide by length of domain, 9 I agree with you, 114.75

*September 12, 2016*

**physics**

total momentum = 0 3*5 = 2*s s = 7.5 m/s in opposite direction

*September 12, 2016*

**physics**

That is distance (scalar) not displacement (vector) angle west of north = A tan A = 15/20 = 3/4 = .75 A = 36.9 deg west of north or 360 - 36.9 = 323.1 degrees true

*September 12, 2016*

**maths**

area = (1/2) d1 d2 84 = (1/2)(12) d2 d2 = 84/6 = 14

*September 12, 2016*

**Algebra**

27*10^11 is correct Are you typing your response on a computer? Perhaps try * instead of the letter x

*September 12, 2016*

**math**

y = 3 z z + x = 36 y + x = 72 ------------ z - y = -36 so z = y-36 y = 3 (y-36) 2y = 3*36 y = 3*18 = 54

*September 12, 2016*

**Algebra**

1.2*5.9 * 10^19

*September 12, 2016*

**math**

http://www.jiskha.com/display.cgi?id=1473658340

*September 12, 2016*

**Algebra**

1.57*10^-1

*September 12, 2016*

**Algebra**

5.0800 * 10^4

*September 12, 2016*

**Math**

d = 30 t d = (1/2)(2.44)t^2 so 30 = 1.22 t t = 30/1.22 solve for t and d then v = 2.44 t

*September 12, 2016*

**Math**

V = (4/3)pi r^3 A = 4 pi r^2 4 pi r^2 = 4 pi (16) + 4 pi (64) r^2 = 80 = 16*5 r= 4 * sqrt 5 so (4/3) pi [ 4^3 *5 sqrt 5 ]

*September 12, 2016*

**Math**

You just said she ate two apples.

*September 11, 2016*

**first you try**

You are evidently studying Europe during the Renaissance. The questions are pretty fundamental to that subject. Many of the potential answers are simply inane (creating military alliances with China?). The right ones are the ones that make sense within the context of the ...

*September 11, 2016*

**algera**

t = 3 f 10 t + 50 f = 2080 10 t + 50 (t/3) = 2080 30 t + 50 t = 6240 80 t = 6240 t = 78 tens

*September 11, 2016*

**Sciene Degree**

(124/112)28

*September 10, 2016*

**math**

on number line |-3| is 3 units right of zero but -3 is 3 units left of zero so the difference is 6 units.

*September 9, 2016*

**Physics**

dn = 55*1.3 de = 65*.75 distance = d = sqrt(dn^2+de^2) displacement vector = d at angle of tan^-1(dn/de) north of east average speed = d/(1.3+.75) velocity = displacement vector/(1.3+.75)

*September 9, 2016*

**Science**

length of string ?

*September 9, 2016*

**Math**

68 - 38 =

*September 9, 2016*

**Math**

1/6 = x/1200 x = 1200/6 = 200 yes

*September 9, 2016*

**Geometry**

If the side of the cube is longer than 42 it sticks out of the prism. Two of them will fit in there because the prism is twice as long as the cube. (84 = 2 * 42) Obviously if you make that 84 length smaller, only one will fit in.

*September 9, 2016*

**science**

LOL, is the question about time on a digital clock or numbers?

*September 9, 2016*

**College mathematics**

48 cookies/.5 cups = 96 cookies/1 cup 2.25 cups * (96 cookies/cup) = 216 cookies

*September 9, 2016*

**math**

a + b = 14 a - b = 40 ============ add 2 a = 54 a = 27 b = 14 - 27 = - 13

*September 9, 2016*

**Math**

Did you try 15 and 20 ??

*September 9, 2016*

**Physics**

88.3 = (1/2) g t^2 88.3 = .5 * 23.6 * t^2 t = 2.74 seconds

*September 9, 2016*

**PHYSICS**

period = T = 1/f = 1/510 second distance in one period = 340(1/510)meters distance in 250 periods =250*340/510

*September 9, 2016*

**TYPO**

v at 19.5 = v at 8.5 + 10*11 = 105 + 110 = 215 meters/second at 19.5 that is average speed from t = 19 to t = 20 so 215 meters

*September 9, 2016*

**Science**

at 4.5 seconds it is going 65 m/s at 8.5 seconds it is going 105 m/s a = change in v / change in time a = 40/4 = 10 m/s^2 so 19.5 - 8.5 = 11 seconds v at 19.5 = v at 8.5 + 10*11 = 8.5 + 110 = 118.5 meters/second at 19.5 that is average speed from t = 19 to t = 20 so 118.5 meters

*September 9, 2016*

**copy and paste does not work here**

We can not see your list.

*September 8, 2016*

**math**

89 degrees 59 minutes 60 seocnds - 78 degrees 00 minutes 43 seconds =

*September 8, 2016*

**Physics**

I do not know the mass of the bullet but energy = (1/2) m v^2

*September 8, 2016*

**Physics**

mv rocket = m v exhaust so d/dt (mv rocket) = d/dt (mv exhaust) m v rocket = (50 - 2 t)v = m v exhaust = (2t)1000 50 v - 2vt = 2000 t 50 dv/dt -2v - 2t dv/dt = 2000 at t = 0 and v = 0 50 dv/dt = 50 a = 2000 a = 40 m/s^2

*September 8, 2016*

**Math**

-1 = 12 x - 42 + 22 19 = 12 x x = 19/12

*September 7, 2016*

**Physics**

Ke = (1/2) m v^2 work done = F d where F = .68 m g so .68 g d = (1/2) v^2

*September 7, 2016*

**maths**

x^2 + x^2 = 50 x^2 = 25 x = 5

*September 7, 2016*

**Math**

(7+10+14 + x) = 4*15 31 + x = 60 x = 29

*September 7, 2016*

**math**

23/4 = 5 with remainder 3

*September 6, 2016*

**Physics**

3 sin A = 1.7 where A is the angle upstream from straight across

*September 6, 2016*

**Math Help**

6/10 + 7/10 = 13/10 needed each bag is 8/10 so two bags is enough, 16/10 from the secondbag 3/10 is left over plus the entire third bag so remainder = 11/10 or 1 1/10

*September 6, 2016*