Wednesday

October 26, 2016
Total # Posts: 27,556

**Physics**

50 * 9.81 * 2.4 = about 1200 J If you say g = 10m/s^2 you get exactly 1200 J

*August 31, 2016*

**Physics**

a = change in velocity/change in time = -20/4 = -5 m/s^2 F = m a = -300*5 = -1,500 Newtons

*August 31, 2016*

**math**

x^-n = 1/x^n 5 * 10^-2 = 5/10^2 = 5/100 = 0.05

*August 30, 2016*

**math**

( distributive property :)

*August 30, 2016*

**math**

if I have 100 dollars and increase that by 5% I then have 100*1 + 100*0.05 which is 100 (1.05)

*August 30, 2016*

**Physics**

s is initial speed Vi = s sin 6 v = Vi - g t at top v = 0 t = s sin 6 / 9.81 u = s cos 6 11 = u t t = 11/(s cos 6) so 11/(s cos 6) = s sin 6/9.81 solve for s, the initial speed get t then h = .39 + Vi t - 4.9 t^2 for part b u = s cos 6 new u = .25 s cos 6 then t to fall from h...

*August 30, 2016*

**Physics**

Now I did the squash one. Based on that you should be able to do this one.

*August 30, 2016*

**Pre-Calculus**

sec = 1/cos note cos is 0 at pi/2 so sec is undefined there (infinite + or -) in quadrant I cos is + so sec is + but in quadrant II cos is - so sec is - note cos always </= |1| so |sec| always >/= |1| that should help with your graph

*August 30, 2016*

**math**

It is divisible by 2

*August 30, 2016*

**Pre-Calculus**

y = sin x what values can x have? any real number right? y = sin^-1 x what values can x have? Only between -1 and + 1 right?

*August 30, 2016*

**physics**

you drove how long at 95? 180 km / 95 km/hour = 36/19 hour (45/10 - 36/19)hours at 65 about (90/20 - 36/20)65 = 54*65/20 = 175.5 km approximately 175 + 180 = 355 km approximately I do not feel like turning my calculator on. You can do it accurately.

*August 30, 2016*

**Math**

1 gallon (12 miles/0.3 gal) = 120/3 = 40 miles

*August 30, 2016*

**Math**

You are welcome.

*August 30, 2016*

**Math**

k^10 v^13

*August 30, 2016*

**Math**

4,020,561,340 add 0*10^0 4*10^1 3*10^2 1*10^3 6*10^4 5*10^5 0*10^6 2*10^7 0*10^8 4*10^9 :)

*August 30, 2016*

**History**

I would vote for the riches :) He was quite sure the world was round as were most navigators but he far underestimated the diameter and therefore thought he was in the East Indies when in fact he was in the West Indies :)

*August 30, 2016*

**Science**

All correct.

*August 30, 2016*

**Math**

60 person days/job (1/60) job/person day (1/60)job/person day *(4) persons = 4/60 job/day = 1/15 job/day so 15 days

*August 30, 2016*

**math homework**

5^2 + 12^2 + 9^2 = 250 length = sqrt 250 = 5 sqrt 10 so (1 / 5sqrt10) (-5,-12,9)

*August 30, 2016*

**typo, please check what youi posted**

-9, 12, 21 You have a typo Please proofread before you post http://www.gregthatcher.com/Mathematics/GaussJordan.aspx

*August 30, 2016*

**Physics**

time outbound = d/48 time back = d/340 so d/48 + d/340 = 1.2 (.0208333 + .00294)d = 1.2 d = 50.5 meters

*August 30, 2016*

**Math**

q q * - n * - d * n q * - n :( - d :( d q * - n :( - d :( so 5/9

*August 29, 2016*

**Math - Check please!**

I agree you.

*August 29, 2016*

**ALGEBRA**

put these two points on a number line one is four to the left of zero and the other is 21 to the right of zero so the total distance between them is 21 + 4 = 25 or write 21 - (-4) = 21 + 4 = 25

*August 29, 2016*

**physics**

Xa = -5.3 + 8.1 t Xb = 4.7 - 7.8 t so when they meet Xa=Xb -5.3 + 8.1 t = 4.7 - 7.8 t 15.9 t = 10 so t = 10/15.9 then Xa = x for example = -5.3 + 8.1(10/15.9)

*August 29, 2016*

**Math**

6*9 = 54 so -54 beads

*August 29, 2016*

**Math**

done that above, -54

*August 29, 2016*

**Chemistry**

Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...

*August 28, 2016*

**physics**

What if the highway runs north-south?

*August 28, 2016*

**typo**

They have to tell you the mass.

*August 28, 2016*

**PHYSICS**

He ends up going 200 meters west in 252 seconds. Therefore we an figure out his west velocity component: Vw = 200/252 m/s Meanwhile he is carried south at .5 m/s so he will have to have a north component of Vn = .5 m/s So we can figure the angle north of west he has to head. ...

*August 28, 2016*

**physics**

weight down = 8 * 9.81 T up so m = hanging mass m a = F 8 a = 8*9.81 - T and top mass T = 5 a so 8 a = 8*9.81 - 5 a 3a = 8*9.81 a = 8 * 9.81/3 T = 5 * 8 * 9.81

*August 28, 2016*

**physics**

a = -3 m/s^2 v = Vi + a t at stop 0 = 20 - 3 t t = 20/3 (they should have started at 21 m/s) d = Vi t + (1/2) a t^2 d = 20 (20/3) - 3/2 (20^2/3^2) = 20^2/3 - 20^2/6 = 20^2/6 = 400/6 = 200/3 or easy way for second half is average speed during stop = 10 10 (20/3) = 200/3

*August 28, 2016*

**Maths**

y = 2x+8 y = 50 - x so 2x+8 = 50-x 3x=42 x = 14 y=36

*August 27, 2016*

**Math**

huh? (y2-y1) = -5-3 = -8 (x2-x1) = -2 +10 = 8 so slope = -8/8 = -1 so y = -1 x + b use either point now 3 = -1(-10) + b b = -7 so I get y = -x -7 ================ check that with the other point -5 = 2 -7 sure enough

*August 27, 2016*

**physics**

a = change in velocity/change in time = 495/1.78 m/s^2 braking is opposite velocity a = -495/2.16 m/s^2 note the acceleration of gravity is about 10 m/s^2 so this is more than 25 g,scary.

*August 27, 2016*

**Chemistry**

Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...

*August 27, 2016*

**physics**

weight = normal force = m g = 50 * 9.81 Newtons static force = .4 * 50 * 9.81 moving force = .3 * 50 * 9.81 assume use entire static force or it will not accelerate .1*50*9.81 = m a = 50 a so a = .981 m/s^2 v = a t = .981 * 5

*August 27, 2016*

**physics**

g = 9.81 m/s^2 v = Vi - g t at top v = 0 t = 25/9.81 seconds to top double that for time in air m g h = (1/2) m Vi^2 h = 625/(2*9.81) v is 0 at top of course a is -9.81 m/s^2 forever until it hits the mud.

*August 27, 2016*

**Computer Applications**

maybe something like this: n = 101 sum = 101 1 if n = 199 quit n = n+2 sum = sum + n go back to 1 quit ---> print the sum and end

*August 27, 2016*

**physics**

In the Google search engine input: 40 mph = km/h You will find 64.3738 km/h which is 62373.8 meters/h which is 62373.8 meters/h (1 h/60 min) in meters/min times 3 for 3 minutes 64.3738 km/h * 1 h/3600 s) * t = 1 km so t = 3600/64.3738 seconds

*August 27, 2016*

**Physics. Pleaseee helpppp**

calculate the potential energy in the center 4 k 2 Qe^2/half diagonal^2 then calculate it at the center of a side 2 k 2 Qe^2/ half side^2 + 2 k 2 Qe^2/diagonal^2 the difference in potential energy is the work done

*August 27, 2016*

**Physics**

short answer: 40% above water 60% below water :) long answer: volume of wood = 60 kg (1 m^3/600kg) = 0.1 m^3 volume of wood under water (see Archimedes) = 60 kg (1 m^3/1000kg) = 0.06 m^3

*August 27, 2016*

**Science**

step by step do [sqrt(16+9)]^2 = 5 sqrt(25+144) = sqrt(169) =13 or simply sqrt (16+9+144)

*August 27, 2016*

**math**

half length of diagonal = 8 look at B to center of that diagonal now have 8, 6, 10 right triangle area of that triangle = (1/2)8 *6 there are 4 of those trianges on the rhombus 16 * 6 = 96 or half product of diagonals (1/2)(16*12) = 96

*August 27, 2016*

**math**

http://www.wikihow.com/Calculate-the-Area-of-a-Rhombus

*August 27, 2016*

**Chemistry**

Dissolved 0.7500 g calcium chloride dihydrate and impure, in distilled water and the volume was elevated to 200.00 mL in a volumetric flask. A rate of 10.00 mL of the same consumed the titration 18.9 mL 0.0125 M EDTA using CALCON as indicator. What is the purity of the salt...

*August 26, 2016*

**math**

make a list take differences ---- 71 ** 16 87 ** 16 98 ** 16 110 the differences are all 16 71-16 is the answer :) 55

*August 26, 2016*

**Algebra**

It is a straight line when y = 0, x = 8 so put a dot on the x axis at x = 8 when x = 0, y = -8/5 = - 1.6 so put a dot on the y axis at y =-1.6 Draw a straight line through those two dots. The end

*August 26, 2016*

**MATH HELP**

|-3| = 3 |+3| = 3 so two numbers on a number line have the same absolute value , |-3| and |+3|

*August 26, 2016*

**Physics**

d = (1/2) g t^2 = 4.9 t^2 at t = 0, d = 0 at t = 1, d = 4.9 at t = 2, d = 4.9*4 at t = 3, d = 4.9 * 9 so from t = 1 to t = 3 it falls 4.9 (9-1) = 4.9*5

*August 26, 2016*

**Math**

60 = 10*6 = 5*12 12-5 = 7 remarkable

*August 26, 2016*

**Algebra**

(x-1)^2+(y-2)^2 = r^2 (-4-1)^2 + (-3-2)^2 = r^2 that should get you under way.

*August 26, 2016*

**Algebra**

I told you all but B and E Make sure you understand C, how to express a repeating decimal as a ratio of whole numbers (rational) using infinite geometric sequence.

*August 26, 2016*

**Algebra**

any number with pi in it is not rational. any number with sqrt 7 in it or sqrt 2 in it is not rational all the others can be expressed as a ratio of whole numbers. 13/1 3.454545454545..... = 3 + 45/100 + 45/10,000 + 45/ 1,000,000 etc = 3 + 45/100 + 1/100 (45/100)+ 1/100^2 (45/...

*August 26, 2016*

**Geomentry**

5526316/10,000,000

*August 26, 2016*

**english**

her wrist weighs 100 pounds???? LOL

*August 26, 2016*

**Physics**

you need to know how many cm of rain fell and the area of the city. 1 cm^3 = 10^-3 kg = 10^-6 tons need depth of water in cm * area of city in cm^2 to get volume in cm^3 multiply that by 10^-6 to get tons.

*August 26, 2016*

**math**

do you mean? | 3 7 8 | | 2 2 6 | | 7 9 3 |-| 6 7 8 | | 7 9 9 | | 5 8 6 | is | 1 5 2 | | 1 2-5 | | 2 1 3 |

*August 26, 2016*

**math**

hey, I did the one above.

*August 26, 2016*

**math**

That comes out 4,34/3,26 so I think you gave me another typo.

*August 26, 2016*

**math**

http://www.gregthatcher.com/Mathematics/GaussJordan.aspx

*August 26, 2016*

**math**

1/6 x = 1/8 y - z = -24 assume you mean 1/6 x + 1/8 y - z = -24

*August 26, 2016*

**math**

3 5 seems pretty obvious

*August 26, 2016*

**math**

a) 12 * 250 = b) 12 * 250 * 100 / 22,000 =

*August 26, 2016*

**12th grade physics**

1000cos[ sin^-1 (15/40) ] or 1000 [ sqrt(1600-225)]/40

*August 26, 2016*

**Social Studies (Check Answers) Last Time**

14 I disagree with you.

*August 25, 2016*

**Pre-calculus**

vertex at point (v,v) axis parallel to x, opening right (y-v)^2 = 4a(x-v) so (-2-v)^2 = 4 a (6-v) and ( 4-v)^2 = 4 a (3-v) ======================now plug and chug 4 + 4v + v^2 = 24 a - 4 a v 16- 8v + v^2 = 12 a - 4 a v ----------------------------- -12 +12v = 12 a or a = v-1 4...

*August 25, 2016*

**Calculus**

dV = surface area * dr for a sphere dV = 4 pi r^2 dr dV/dt = 4 pi r^2 dr/dt 5 = 4 pi r^2 (3) r^2 = 5/(12 pi)

*August 25, 2016*

**METRIC CONVERSION**

0.86 http://www.google.com/search?q=8.6+dm+meters&ie=utf-8&oe=utf-8

*August 25, 2016*

**Algebra check answers**

Choose the best definition for the following term: variable A. A letter that holds the place for some unknown value in mathematics*** Yes Question 2 Choose the best definition for the following term: substitution C. A process where if two things are equal, one can be put in ...

*August 25, 2016*

**World history.**

I vote for c. but miss e. it had tax collectors and slave drivers

*August 25, 2016*

**physics**

potential energy at top = kinetic energy at bottom m g h = (1/2)m v^2 so h = v^2/(2g) = 225/(2*9.81) about 11 meters

*August 25, 2016*

**Algebra**

yes, the second number has to be -1 :)

*August 25, 2016*

**Physics**

m = spaceship mass = 3.3*10^5 M = asteroid mass = 8.7*10^17 R = 7,300,000 m = 7.3*10^6 meters F = m a = m v^2/R F = G m M/R^2 + k |Q1| |Q2|/R^2 (both forces +, attraction) so v^2 = G M/R + k |Q1| |Q2|/(m R)

*August 25, 2016*

**math**

yes, distributive properrty

*August 25, 2016*

**MATH**

(11+x)/(15+x) = 7/8 88 + 8 x = 105 + 7 x x = 17

*August 25, 2016*

**?**

How did you go from 134.05 hp to 13.05 hp ?

*August 25, 2016*

**ALG 2**

It said the length was twice, not half.

*August 25, 2016*

**ALG 2**

4*9 = 36 so garden length is 9 so n = 4.5

*August 25, 2016*

**Math**

∫cos^6 x dx note: ∫cos^n dx=[cos^(n-1)x /n sin x]+(n-1)/n ∫cos^(n-2)x dx and ∫cos^2 x dx = x/2 + sin 2x /4

*August 25, 2016*

**SOUND**

compression wave in material

*August 25, 2016*

**Maths**

draw triangle center to bisect chord. draw altitude from circle center of to chord center. right triangle legs 5 and 4, hypotenuse is radius sqrt (25 + 16) = sqrt(41)

*August 25, 2016*

**math**

30*6.50 = 195 300 - 195 = 105 needed in tips 105 = .20 * x x = 525

*August 24, 2016*

**Math**

j = b - 2 b = .5 m so j = .5 m - 2 m = 2 b b = j + 2 etc etc etc

*August 24, 2016*

**PHYSICS**

huh? circumference = 2 pi R

*August 24, 2016*

**Math**

You are welcome.

*August 24, 2016*

**Math**

3^3 = 27 (x^4)^3 = x^12 so 27 x^12 y^3

*August 24, 2016*

**math**

n-1 , n , n+1 n+1 = .5 (n-1) + 2 I guess, English not clear n+1 = .5 n - .5 + 2 .5 n = .5 n = 1 so 0 , 1 , 2

*August 24, 2016*

**math**

If you subtract nothing from twenty you still have twenty.

*August 24, 2016*

**physics vectors**

x direction: 6 a - 8 b + 25 = 0 y direction: -8 a + 3 b + 22 = 0 ========================== 24 a - 32 b + 100 = 0 -24 a + 9 b + 66 = 0 -------------------------add - 23 b + 166 = 0 b = 7.22 a = 5.46 check my arithmetic !

*August 24, 2016*

**MATH**

LOL, yes :) good

*August 24, 2016*

**MATH**

http://www.mathsisfun.com/algebra/sequences-sums-arithmetic.html Xn = a +(n-1)d 96 = a + 13 d 173 = a + 24 d --------------- -77 = -11 d d = 7 then a = 96 - 13*7 = 5 so X19 = 5 + 18*7 = 131 etc

*August 24, 2016*

**pre calculus honors**

try a. 10+2+3 = 15 yes 70+2+3 = 75 yes 30+2-3 = 29 yes so a works, the end :)

*August 24, 2016*

**MATH**

well, a = 6, given and d = 7 given Xn = 6 + (n-1)7 X6 = 6 + 5*7 = 41 X15 = 6 + 14*7

*August 24, 2016*

**MATH**

Now you did the one above, you can do this one.

*August 24, 2016*

**pre calculus honors**

but I cheated. [ used a = dV/dt = d/dt (dx/dt) ]

*August 24, 2016*

**pre calculus honors**

which is the acceleration of gravity on earth in ft/s^2 and indeed it works ;)

*August 24, 2016*

**pre calculus honors**

I wonder if a comes out -32 ft/second^2 :)

*August 24, 2016*