Thursday

June 30, 2016
Total # Posts: 26,400

**Physics II**

m = mass of electron q = electron charge F = m a q E = m a a = q E/m v = Vi - a t v = 0 at stop so t = 5 * 10^5/a d = Vi t - .5 a t^2 .09 = 5*10^5 t - .5 a t^2 now the easy way :) if acceleration is constant the average speed during this stop is 2.5 *10^5 m/s it stops in .09 m...
*January 24, 2016*

**Math**

He works two and then four more for a total of six ? 2 + 4*4 = 18
*January 24, 2016*

**math**

a + ar + ar^2 ...+ ar^(n-1) a = 3 a r+ a r^2 = 60 r + r^2 = 20 r^2 + r - 20 = 0 (r-4)(r+5) = 0 r = 4 3 + 12 + 48 .... 3 * 4^(n-1)
*January 24, 2016*

**physics**

m (g - v^2/r)
*January 24, 2016*

**physic**

change of momentum = Force * time = 200 * s If you really mean for s seconds.
*January 24, 2016*

**phy 231**

horizontal problem: u = 338 cos 40.5 = 257 m/s x = u t = 257 * 8.09 h = Vi t - 4.9 t^2 where Vi = 338 sin 40.5 = 220 m/s h = 220(8.09) - 4.9 (8.09)^2
*January 24, 2016*

**Been there - use d = v t **

http://www.jiskha.com/display.cgi?id=1453604915 Yes, it is composite, so use d = v t which was part B and please use one name so I do not have to search all over for your earlier attempt.
*January 24, 2016*

**Physics**

initial momentum east = 3 * 1 - 5 * 2 = -7 so final momentum east = -7 I guess left is west, negative -7 = 3 * -1 + 5 * u 5 u = -4 u = 4/5 west
*January 24, 2016*

**physics**

Vertical problem: v = a t x = Xi + Vi t + .5 a t^2 here x = 0 Xi = 49.1 Vi = 0 a = -9.8 0 = 49.1 + 0 t - 4.9 t^2 so a) t = sqrt ( 49.1 m/4.9 m/s^2 ) b) v = -9.8 t c) u = 12.6 v = -9.8 t tan(angle from horizontal) =(v/u)
*January 24, 2016*

**Physics**

a = 710/275 v = a t t = 20 * 275 / 710 seconds
*January 24, 2016*

**physics**

assuming the weight is evenly distributed radius = .04 meters pi r^2 * P = 400 P = 400/.00503 = 79577 Pascals or about .8 atmospheres
*January 23, 2016*

**Math**

Area = 2400 ft^2 2400 (2/12) = 400 cubic feet(7.48 gal/ft^3 = 2992 gallons
*January 23, 2016*

**Math**

for P sin T is -1 when T = (3/4)(2pi) = 3 pi /2 for Q sin T then becomes +1 when sin T = 2 pi + pi/2 = 5 pi/2 ------------------------ now x for P 6 pi x = 3 pi/2 x = 1/4 and y is -2 now x for Q 6 pi x = 5 pi/2 x = (5/12) and y is +2 slope = 4/(5/12 - 1/4) = 4 / (5/12 - 3/12...
*January 23, 2016*

**physics**

F = 800 - 300 = 500 N a = F/m = 500/400 = 1.25 m/s^2
*January 23, 2016*

**Math**

so d = v t
*January 23, 2016*

**Math**

what is that x about? d is distance traveled k is hypotenuse 10 , not (10+x) is original distance leg k = sqrt (d^2 + 100) d = v t Is c) the dot product of k and d? I do not understand your notation If it is k dot d then that is |k| |d| cos angle between path direction and ...
*January 23, 2016*

**Physics**

m = mass of proton q = charge of proton During first E1 F = q E1 north a = q E1/m north vfinal = (q/m) E1 (14.8) x final = 0 + 0 +.5 (q/m)E1 (14.8)^2 = (q/m)E1 (110) Now during E2 x initial = 110 (q/m)E1 Vinitial = (q/m)E1 (14.8) x final = 0 so 0 = 110(q/m)E1 + 14.8(q/m)E1(8....
*January 23, 2016*

**Math**

Well, anyway, the Physics was easy :)
*January 23, 2016*

**Physics**

cool :)
*January 23, 2016*

**Physics**

By the way, of course they had the same momentum at rest.
*January 23, 2016*

**Physics**

That was intended to be a trick, confusing question, but you did not fall for it :)
*January 23, 2016*

**Physics**

work done = F * distance in this case the work done goes straight into increasing the kinetic energy F * d = increase in Ke same for both one to one the end.
*January 23, 2016*

**Physics 30**

To start: Potential energy of 3 kg box up .5 = m g h = 3*9.81*.5 14.72 Joules 3 kg hit floor point: Potential energy of 2 kg box now = 2 * 9.81 * .5 = 9.81 Joules SO 14.72 - 9.81 = 4.92 Joules is in the kinetic energy of the two moving blocks, m = 3+3=5 kg (1/2)(5)v^2 = 5 v = ...
*January 23, 2016*

**physics**

I bet her class uses g = -10 m/s^2 so it came out zero.
*January 23, 2016*

**physics**

And that one with the truck and the car bothered you ?
*January 23, 2016*

**Calculus**

W = (1/2) k x^2 where x is the stretch or compress length here x = .36 - .28 = .08 meter so 5 = .5 k (.0064) k = 1563 N/m so (1/2) k = 781 a) work to .34 - work to .32 subtract the .28 from both .06 and .04 = 781 (.06^2-.04^2) =1.562 J b) F = k x 15 = 1563 * x x = .00960 m = ....
*January 23, 2016*

**Calc 1**

The sin function range is between -1 and +1 1.7321 is not the sin of any angle.
*January 23, 2016*

**Chemistry**

6 g of M is 6/27 mol 23.66 g of Cl is 2/3 mol 2/3 = 14/27 so there are 14 Cl atoms for every 6 atoms of M ratio is 3/7 M/Cl M3Cl7
*January 23, 2016*

**Math**

there are 2 cups in a pint so 5 pints = 10 cups 4 cups/10 cups = 2/5
*January 23, 2016*

**math**

s = 3 c - 20 s = 180 - a c = 90 - a -------------subtract s - c = 90 so s = c+90 c+90 = 3 c - 20 2 c = 110 c = 55 then s = 145 s/c = 145/55 = 29/11 ================= check ================= 3(55)= 20 = 165 - 20 = 145 yes a = 90 -c = 35 180 - 35 = 145 yes
*January 23, 2016*

**maths**

4 c + 8 a = 380 c = a - 10 ==================== substitute (a-10) for c 4 (a -10) + 8 a = 380 12 a - 40 = 380 12 a = 420 a = 35
*January 23, 2016*

**Physics**

v = Vi - 9.81 t at top v = 0 so t = Vi/9.81 at top 34 = 0 + Vi t - (9.81/2) t^2 34 = Vi^2/9.81 - Vi^2 /(2*9.81) 34 = Vi^2/(2*9.81) Vi = 25.8 m/s
*January 22, 2016*

**physics**

momentum = m v = 1200 * 30 kg m/s Ke = (1/2) m v^2 = 600 * 900 Joules 30/2 = 15 v^2 = (1/2)30^2 = 900/2 = 450 so v = sqrt (450) = sqrt (9*50) = sqrt(3*3*5*5*2) = 15 sqrt 2 v = 21.2 m/s
*January 22, 2016*

**Ms sue or damon pls help me with mathhhhhhhhhhhhh**

9/12 = 3/4 foot 6/12 = 1/2 foot so Volume = 7 * 1/2 * 3/4 = 21/8 ft^3 (21/8) / 2.625 = 2.625/2.625 = 1 bag. I guess he built the box to hold one bag :)
*January 22, 2016*

**physics**

(1/2) m v^2 = .5 *10 * 16 = 80 Joules
*January 22, 2016*

**engineering science**

work = Force * distance in direction of force I do not see your picture but assume you are pushing 420 meters in the direction of the push W = 615 * 420 Joules
*January 22, 2016*

**Calculus**

parabola with vertex at x =-1 and y = 0 then proceeding right above and below the x axis passing through (0,1) and (0,-1) ∫ left of x = 0 = ∫ right of x = 0 because of symmetry we only need to do + y y = +/-sqrt (x+1) = +/-(x+1)^.5 ∫ y dx from -1 to 0 = &#...
*January 22, 2016*

**physics**

1. The mass in kg is mass PERIOD EVERYWHERE 2. The weight, or in other words gravitational FORCE is the mass times the local acceleration of gravity: F = W = m g on earth mg= 400*9.8=3920 Newtons on the moon g is about 1/6 g on earth so on moon mg = (1/6)*9.8*400=653 N
*January 22, 2016*

**I do not know /unanswerable question**

Because of the gear ratio between pedal and wheel rim I have no idea how fast her foot moves to make the bike go 8m/s. Different gears give different foot forces for the same bike speed.
*January 22, 2016*

**Huh**

What do you mean? Use parentheses.
*January 22, 2016*

**math**

x^2 - 3 x - 7/2 = 0 x = [ 3 +/-sqrt (9+14) ]/2 A = [ 3 + 23]/2 = 13 B = [ 3 - 23] / 2 = -10 (a) (x- A/B)(x-B/A) = 0 (x +13/10)(x+10/13) = 0 x^2 + (269/130) x + 1 = 0 130 x^2 + 269 x + 130 = 0 etc etc etc
*January 22, 2016*

**Science**

But you show Na O and Cl (but you show O as 0 Sodium Hypochlorite has oxygen in it, not zero) the only one left is H
*January 22, 2016*

**Trigonometry**

I assume you mean degrees and not minutes h is the height we want x is distance to the monument from the closer point tan 38 = h/x tan 32 = h/(55+x) x = h/tan 38 = 1.28 h tan 32 = h/(55 + 1.28 h) 34.4 + .8 h = h h = 172
*January 22, 2016*

**Science**

LOL, is it the filtered orange juice ? The answer is the only chemical element mentioned here, Hydrogen peroxide.
*January 22, 2016*

**physics**

I guess the boat is anchored? 6 m/2 s = 3 m/s Note: That is the speed of the crest or "phase velocity". The speed of the group of waves, the "group velocity" is (1/2) of that if they are deep water waves. Energy is propagated at the group velocity. In real ...
*January 22, 2016*

**Algebra 2 pt 2**

here is the height versus time t h = 70 + 150 t - 16 t^2
*January 22, 2016*

**math**

(7/8)(4/5) = (7/5)(1/2) = 7/10 = 0.7 yards^2 7/20 = 0.35
*January 22, 2016*

**Algebra 2**

here is the height versus time t h = 70 + 150 t - 16 t^2
*January 22, 2016*

**Algebra 2**

Well, who does feet any more but anyway in that system g = -32 ft/s^2 v = Vi - g t v = 150 - 32 t at the top, v = 0 so 0 = 150 - 32 t t = 4.69 seconds to the top h = Hi + Vi t - (1/2)gt^2 h = Hi + Vi t - 16 t^2 h = 70 + 150 t - 16 t^2 so at the top h = 70 + 150(4.69) -16 (4.69...
*January 22, 2016*

**Algebra**

k +(k+4) + 2(k+4) = 36 4 k + 12 = 36 4 k = 24 now you finish
*January 22, 2016*

**science**

change in L/L = 25*10^-6 (T-20) .1/80 = 1/800 = 25* 10^-6 (T-20) T-20 = 10^6/2*10^4 =50 T = 70 deg C
*January 22, 2016*

**physics 1**

cos 69 = h/8.7
*January 21, 2016*

**Physics**

2 pi radians/rev ( 2.5 rev /3.6 s) = 4.36332313 radians/second
*January 21, 2016*

**math**

I do not know if you mean -1 < -(1/5) x or -1 < -1/(5x) I will assume the first. 1 > (1/5)x reverse arrow when multiplying by negative quantity 5 > x or x < 5 ============ always check if x = 0 is -1 < -(1/5) 0 ????? yes -1 < 0
*January 21, 2016*

**Math**

a r^2 = 10 a r^6 = 6250 (10/r^2)r^6 = 6250 r^4 = 625 = 25*25 = 5*5*5*5 so r = 5
*January 21, 2016*

**compounded errors :(**

dF/dr = -2kr/r^4 = -2 k/r^3 so dF = (-2 k /r^3) dr
*January 21, 2016*

**science, typo left k out**

dF/dr = -2rk /r^2 so dF = (-2k/r)dr
*January 21, 2016*

**science**

by the way the difference in R between one side of earth is tiny compared to R If you have had calculus think: F = k/r^2 dF/dr = -2r /r^2 so dF = (-2/r)dr so you can calculate a small change in F due to a small change in r
*January 21, 2016*

**science**

I assume you can do F = G Msun Mman / R^2 but the tide is more complicated and depends on the moon. Look at: http://scijinks.jpl.nasa.gov/tides/
*January 21, 2016*

**math**

120 + 2 x = 180 x = 30 degrees for the other two angles cos 30 = (YZ/2)/6 cos 30 = yz/12 yz = 12 cos 30
*January 21, 2016*

**math**

(12/21)* 100
*January 21, 2016*

**math**

S = top + bottom + sides top = pi r^2 bottom = pi r^2 sides = 2 pi r h that will be in square inches (in^2) there are 144 square inches per square foot so S * 1500 / 144
*January 21, 2016*

**Pre-cal**

2 [ (b/2)+10 ] + b </= 100 b + 20 + b </= 100 2 b </= 80 b </= 40 so 40 cm
*January 21, 2016*

**Chemistry**

Iron must be wicked expensive where you live.
*January 21, 2016*

**social studies**

No problem, good luck :)
*January 21, 2016*

**social studies**

Not my thing, but I thought their thing was calendars.
*January 21, 2016*

**Chemistry**

Half as many O2 molecules produced as H2O2 molecules disintegrated
*January 21, 2016*

**Calculus**

no |-1| = 1
*January 21, 2016*

**Physics**

m g h / time 40 * 10 * 30 * .15 / 6 in Joules per second or watts
*January 21, 2016*

**Woodrow Wilson**

There are good things to say about him, but consider: http://www.nationalreview.com/article/345274/progressive-racism-paul-rahe
*January 21, 2016*

**Science**

He swung one of the bats with all his might, (but bunted with the other?)
*January 21, 2016*

**Science**

6. seems to be missing. I disagree about 8.
*January 21, 2016*

**SCIENCE ASAP HELP PLEASE**

NO !
*January 21, 2016*

**SCIENCE ASAP HELP PLEASE**

mass of earth = 5.98 * 10^24 kg Venus 4.82 * 10^24 radius of earth = 6.38 * 10^6 m Venus 6.31 * 10^6 for comparison: Jupiter mass = 1.89*10^27 kg and r = 7.18*10^7 m
*January 21, 2016*

**Check 2 of my world history answers??**

Please do. That is what it is about.
*January 21, 2016*

**Check 2 of my world history answers??**

Hoover was a modern Republican before his time. No way he would raise taxes or take over businesses. He decided to leave the problem to his successor. He was a good engineer though.
*January 21, 2016*

**Check 2 of my world history answers??**

Read John Steinbeck, "Grapes of Wrath".
*January 21, 2016*

**Check 2 of my world history answers??**

No, drought and resulting dust clouds over the plains caused by the farmland drying out and blowing in the wind was a major problem. I wonder what on earth "lack of stock available" means.
*January 21, 2016*

**Math**

(x+h)^3 = (x+h)(x^2 + 2 hx + h^2) = x^3 + 2 h x^2 + h^2 x + 1 h x^2 +2h^2 x + h^3 -------------------------- = x^3 + 3 h x^2 + 3 h^2 x + h^3 now subtract x^3 f(x+h) - f(x) = 3 h x^2 + 3 h^2 x + h^3 NOW let x = 1 :) = 3 h + 3 h^2 + h^3 ========================== Now I did that ...
*January 21, 2016*

**Math**

7 * 4 = 28 28+3 = 31 so we have 31/7 pounds divide by 4 31/28 1 3/28 pounds
*January 21, 2016*

**Science physic**

force * distance = work done = change in potential energy = m g h F * .5 = 60 * 9.81 * .5
*January 21, 2016*

**geometry**

Your figure does not show here. However if it has center at (a , b) then it is (x-a)^2 + (y-b)^2 = r^2
*January 20, 2016*

**Social studies**

the vice president also serves as the ?
*January 20, 2016*

**Physics**

initial momentum = .021 *195 final momentum = (.021+1.6)Vi Vi = 2.53 (1/2) m Vi^2 = m g h h = Vi^2/2g
*January 20, 2016*

**Math**

Maybe you mean triple? if so 3 = (x)^5 log 3 = 5 log x log x = .095424 x = 1.2457 so 24.6 %
*January 20, 2016*

**maths**

4*3*9 = 108 50 + 12*25 = 350 350 - 299 = 51 10^6/10^3 = 10^3 = 1000 8cm / 8 km so 1 cm / 1 km
*January 20, 2016*

**Precalculus**

any point on the perpendicular bisector of AB satisfies your requirement. what is the slope of AB ? slope = (8-2)/(7+5) = 6/12 = 1/2 so the perpendicular has slope m = -2 It must go through the midpoint of AB which is at: x =(7-5)/2 = 1 y = (8+2)/5 = 2 or (1,2) so 2 = -2(1) + ...
*January 20, 2016*

**physics**

what again ? Google Einstein e = m c^2
*January 20, 2016*

**math**

(46 + 35 + 46 + 35) / 100
*January 20, 2016*

**Physics**

Google Einstein e = m c^2
*January 20, 2016*

**physics**

Defining z axis up: area of base of cylinder A= pi r^2 where r = 20 cm = .20 meter height of cylinder = .10 meter volume of cylinder V= pi r^2 h = pi (.2)^2 (.1) weight of cylinder W = g V = 10 V in Newtons b) +W c) -W d) W/A in Newtons/meter^2 or Pascals
*January 20, 2016*

**Physics**

the plane and the shell cover the same horizontal distance in time t T = angle up from horizontal u = 1100 cos T = 600,000/3600 m/s so T = 81.3 degrees so Vi = initial speed up = 1100sin 81.3 = 1087 m/s up how long to reach 2500 meters high? 2500 = 1087 t - 4.9 t^2 4.9 t^2 + ...
*January 20, 2016*

**Math**

10 a + b a + b = 7 so a = (7-b) 10 a + b - 10*2 - 7 = 10 b + a 10(7-b)+b-20-7=10b+(7-b) 70 -10b+b-27=9 b+7 36 = 18b b = 2 then a = 5 so 52
*January 20, 2016*

**actually math - series need math teacher**

Not physics until he jumps
*January 20, 2016*

**Calculus**

∫(2x^5+6x)^3(5x^4+3)dx becomes ∫(u)^3 du/2 = (1/2) ∫u^3 du BUT remember to change b = -1 to 2(-1)^5 +6(-6) =-2 -36 = -38
*January 19, 2016*

**Calculus**

lets' try u = 2 x^5 + 6 x then du = (10 x^4 + 6)dx = 2 (5 x^4+3)dx that looks more promising :)
*January 19, 2016*

**Calculus I think not**

du=x^5+3x+C ?? what is that all abot You add a constant to integral is no constraints on it. BUT NOT to the derivative if u = 5 x^4 + 3 then du = 20 x^3 dx period, the end but that is not what you want to do anyway
*January 19, 2016*

**Calculus**

I assumed you were integrating from 0 to x
*January 19, 2016*

**Calculus**

-(x+1)>0 x+1 < 0 x <-1 I seem to agree but try http://www.wolframalpha.com/input/?i=+integrate+6%2F%281%2B2x+%2B+x^2%29 Which agrees
*January 19, 2016*