# Posts by Scott

Total # Posts: 2,027

**math**

FOIL the two binomials

*March 29, 2017*

**MATH URGENT HELP!**

4% means 1% per quarter (compounding period) 10 yr is 40 quarters A = 5000 (1 + .01)^40

*March 29, 2017*

**Algebra 2**

180º is the negative x direction x = -12.5 , y = 0 (12.5,0)

*March 29, 2017*

**Science**

the trains are closing at 100 kph ... so it takes them 1 hr to pass the plane flies 90 kph for 1 hr

*March 29, 2017*

**Algebra**

should be .94 in last eqn...not .96

*March 29, 2017*

**Algebra**

10000 (1 + .08)^t = 33000 (1 - .06)^t log(10) + t log(1.08) = ... log(33) + t log(.94) t [log(1.08) - log(.94)] = ... log(33) - log(10) t = log(33 / 10) / log(1.08 / .96)

*March 29, 2017*

**Physics**

work is energy your work is correct you might have dropped a digit in the W equation not sure why you don't think you get it...

*March 29, 2017*

**Math**

A is a fixed value the other three vary statistically

*March 29, 2017*

**Math**

those lines around the numbers are absolute value symbols that means only positive numbers |-n| = n

*March 29, 2017*

**Math**

yup

*March 29, 2017*

**Math**

x / y = 3 / 4 4 x = 3 y

*March 29, 2017*

**Math**

$420 is 30% ... you want 3% your answer is ten times what it should be

*March 29, 2017*

**Math**

you're very generous that's a 30% commission

*March 29, 2017*

**MA240 Please help**

good answer

*March 29, 2017*

**Math**

(40 * 18) - 320 check again

*March 29, 2017*

**Chemistry**

a cubic decimeter (dm^3) is a liter not sure what the question is...

*March 29, 2017*

**Physics**

force * distance / time

*March 29, 2017*

**physics**

specific heat * mass * temp change

*March 29, 2017*

**Science**

not tellin' ya the answer but you need to keep thinking

*March 28, 2017*

**MATH**

5/12 (9000 + m) = 250 + m 45000 + 5 m = 3000 + 12 m

*March 28, 2017*

**Mathematics**

might want to check A the others look good

*March 28, 2017*

**chemistry**

100% * (1/2)^(120 / 4.55)

*March 28, 2017*

**ALGEBRA**

the "graphing form" is the vertex form f(x) = a (x - h)^2 + k ... a = 1 in this case vertex is (h,k)

*March 28, 2017*

**Physics**

momentum is conserved 65 kg * 2 m/s = 55 kg * v the canoe moves in the opposite direction

*March 27, 2017*

**Physics**

the index of the solution must be approximately the index of the material there is no refractive boundary between the material and the solution, so the material seems invisible

*March 27, 2017*

**Pre calc**

the height of the observer is ... h = 375 sin(25º) the height of the tower above the observer is ... h = 375 sin(39º) add the two heights to find the tower (remember to round)

*March 27, 2017*

**pre calc**

exact answer is given in "related questions" at bottom of page

*March 27, 2017*

**Algebra**

they each paint a fraction of the house ... the fractions add to one t / 10 + t / 15 = 1 3t / 30 + 2t / 30 = 1 5 t = 30

*March 27, 2017*

**precalc**

a) u - v b) u - 2 v c) 2 u + 4 v

*March 27, 2017*

**Maths**

c = 4 h 2 (c - 280) = h c = 8 (c - 280) solve for c, then substitute back to find h

*March 27, 2017*

**Preclc**

use the Law of Sines to find the distance from one of the people to the spot then use trig to find the height of the spot the angle at the spot is ... 180º - 75º - 45º = 60º 600 m / sin(60º) = x / sin(45º) ... x is the distance from the observer ...

*March 27, 2017*

**Physics**

"acquires" is an interesting term the muscle energy on the ground (like a spring), becomes gravitational potential energy during the jump it appears you have correctly calculated the height

*March 26, 2017*

**Physics**

looks actually correct to me

*March 26, 2017*

**pre calc**

because i made a typo...

*March 26, 2017*

**pre calc**

use the Law of Sines the angle at the ship is ... 180º - 46º - 63º 283 ft / sin(43º) = 350 ft / sin(63º) ... = x / sin(180º - 46º - 63º)

*March 26, 2017*

**algebra**

to save money with B ... A > B .2 m + 40 > .12 m + 56.32 .2 m > .12 m + 16.32 .08 m > 16.32 m > 204

*March 26, 2017*

**Precalculus**

the plane flew 360 mi east in the air but the air moved east and north ... this is the wind speed 15 mi E and 20 mi N forms a 3-4-5 triangle the wind is ... 25 mi / 2 hr ... on a bearing N of E the tangent of the bearing angle is ... 20 / 15

*March 26, 2017*

**math**

twice the teeth means half the revolutions teeth * speed = k = 48 * 3 = 144 96 * s = 144 ... s = 144 / 98

*March 26, 2017*

**physics**

nope E friction from the tires and normal force from the banking

*March 26, 2017*

**Math**

looks like a glass/class typo 2/3 of 30.9 kg 2 * 30.9/3 = ?

*March 26, 2017*

**Pre calc DUE TOMRROW**

i mis-transposed the 43º ... it should be 46º

*March 26, 2017*

**Pre calc DUE TOMRROW**

use the Law of Sines the angle at the ship is ... 180º - 46º - 63º 283 ft / sin(43º) = 350 ft / sin(63º) ... = x / sin(180º - 46º - 63º)

*March 26, 2017*

**geometry**

use ... a^2 + b^2 = c^2 ... twice

*March 23, 2017*

**Pre-cac**

the max is on the axis of symmetry x = 3 / 2a 15 = a (3 / 2a)^2 - 3 (3 / 2a) + 5 10 = (9 / 4a) - (9 / 2a) 10 a = 9/4 - 9/2 = - 9/4 a = -9/40

*March 23, 2017*

**physics**

google "uniform circular motion" look at the diagrams on wikipedia

*March 23, 2017*

**Math**

time = distance / velocity

*March 22, 2017*

**Math**

the peak of the jump lies on the axis of symmetry of the parabola ... x = -b / 2a = -21 / (2 * -16) time up equals time down time of flight (jump) = 2 * 21/32

*March 22, 2017*

**Chem: please help**

new conc = old conc * 15/50

*March 22, 2017*

**Chemistry help!!**

new conc = old conc * 15/50

*March 22, 2017*

**math**

? * (5/2)^2 * (8/2) * 10^6

*March 22, 2017*

**Chemistry**

i think you're right

*March 22, 2017*

**Maths**

2 (x^3 + 6^3) the sum of cubes is a standard factoring

*March 22, 2017*

**math**

the area for the measurements you give is not listed see "Heron's Formula"

*March 22, 2017*

**Math1**

100 (1 + .04)^12

*March 22, 2017*

**math**

.08 f + .05 s = 1330 .12 f + .02 s = 1500 solve the system using elimination or substitution

*March 22, 2017*

**Calculus**

integrate the derivatives Y"=6 ... y' = 6 x + c ... 4 = 6 * 1 + c ... c = -2 y' = 6 x - 2 ... y = 3 x^2 - 2 x + c ... 6 = 3 - 2 + c ... c = 5 y(x) = 3 x^2 - 2 x + 5

*March 22, 2017*

**physics**

a = v / t d = 1/2 a t^2

*March 22, 2017*

**physics/maths help damon or steve or scott**

6 V0 + 18 a = 246 V0 + 9 a = V1 3 V1 + 4.5 a = 69 subs ... 3 V0 + 27 a + 4.5 a = 69 ... times 2 ... 6 V0 + 63 a = 138 subtract to eliminate V0 ... 45 a = -108 ... a = -2.4 substitute back to find V0

*March 22, 2017*

**Physics**

the time of flight is the time it takes for the car to fall the difference in elevation of the two sides 21.3 - 1.8 = 1/2 * 9.8 * t^2 find t the car has to travel 61 m in time t the car's horizontal velocity is constant its vertical velocity increases due to falling ... Vv...

*March 22, 2017*

**Physics**

the energy is proportional to the SQUARE of the compression 4^2 = ?

*March 22, 2017*

**Math**

multiply the percentage (as a decimal) by the total number of students (500) to find out the numbers for the various sports then subtract the basketball number from the football number

*March 21, 2017*

**Math**

the built in Windows calculator (in scientific mode) works pretty well

*March 21, 2017*

**Math**

there are 365 compounding periods per year [1 + (.03 / 365)]^365 = 1 + APY

*March 21, 2017*

**chem**

the pressure is proportional to the absolute (Kelvin) temperature 1.89 / (24.0 + 273) = p / (38.0 + 273)

*March 21, 2017*

**SCIENCE**

for EQUAL branches total r = branch r / # of branches

*March 21, 2017*

**Math**

5.00 + (0.65 * x) = 10.00 + (0.45 * x) .20 x = 5.00

*March 20, 2017*

**Physicd**

7 N?s - 5 N?s = 2 N?s m v = 2 N?s m = 2/5 kg

*March 20, 2017*

**Algebra**

the slope means that the candle shortens by .4 cm per hour of burning how much taller would it be nine hours earlier? (how much did it shrink in nine hours?)

*March 20, 2017*

**math**

s + c = 72 / 3 s - c = 72 / 4 add the equations (to eliminate c) solve for s substitute back to find c

*March 19, 2017*

**math**

m?CAB = m?CBA = 30º m?BCM = 90º BM = 24 ... 30-60-90 TRIANGLE AM = CM

*March 19, 2017*

**science**

RL and LR are brown eyed but carry the blue recessive they represent half of the population

*March 18, 2017*

**math**

there are two "integer" multiples of 2 A 0.25 = 2^-2 B .05 = 2^-1

*March 16, 2017*

**Maths**

each component has an 80% chance of being good so the probability of a good (not defective) product is ... .8^4 probability of a defective product is ... 1 - .8^4

*March 16, 2017*

**Physical Science**

pH + pOH = 14 pOH = 12 [OH] = 10^-12

*March 15, 2017*

**Pre-cal**

s = 2 f - 5 s + f^2 = 115 f^2 + 2 f - 5 = 115 f^2 + 2 f - 120 = 0 (f + 12)(f - 10) = 0 f - 10 = 0 ... f = 10

*March 15, 2017*

**Math**

did you see the two sig fig part? 210000

*March 15, 2017*

**SCIENCE**

think you're right

*March 15, 2017*

**Maths**

the 8th term is 5 differences from the 3rd term, and 7 differences from the 1st term e = 2 t = 2 (f + 2 d) f + 7 d = 2 f + 4 d ... 3 d = f sum8 = 8 f + 28 d = 39 substituting ... 24 d + 28 d = 39 ... 52 d = 39 ... d = 3/4 substitute back to find f

*March 15, 2017*

**math**

there are 36 inches in a yard 580 / 36 = ?

*March 15, 2017*

**11 grade / physics**

Vv = V sin(30º) = ?(2 g h) Vh = V cos(30º) = Vv / tan(30º)

*March 15, 2017*

**Chemistry**

for the given volumes (22.5 + 22.5) * (30.17 - 23.50) * 1.00 ... * 4.184

*March 15, 2017*

**Chemistry 11**

looks fine

*March 15, 2017*

**Math**

the area is the average of the bases, multiplied by the height divide the area by 12 to find the number of boxes needed remember to round up to the next WHOLE number, if necessary

*March 14, 2017*

**Chemistry**

temp change times mass of H2O times specific heat of H2O (37.8 - 21.6) * 100 * 4.179 remember sig fig

*March 14, 2017*

**Physics**

momentum is conserved Mb * Vi = (Mb + Mw) * Vf Vi = (.005 + 8) * 0.50 / .005

*March 14, 2017*

**Physics**

frictional force is the normal force multiplied by the coefficient in this case ... Ff = Ma * g * 0.25 the frictional force keeps A moving with B ... so the max acceleration (without slip) is ... Ma / Ff the max force is the max acceleration multiplied by the sum of the masses...

*March 12, 2017*

**Physics**

1/2 m (v sin(60º)^2 = m g 10 km v = ?(g * 20 km) / sin(60º) this is the minimum velocity for the projectile to reach the height of the plane ... faster would be better

*March 12, 2017*

**Physics**

the weight change in the kerosene is the weight of kerosene displaced by the solid if the solid were kerosene, its weight would be 1.6 g ... (4.8 - 3.2) so the density ratio is ... 4.8 / 1.6

*March 12, 2017*

**Chemistry**

in (a) and (b), the hydroxides are probably in solution and the hydrogen is evolved as a gas

*March 11, 2017*

**pre calc**

the full solution is in the related questions at the bottom of the page

*March 11, 2017*

**pre calc**

the two given population numbers only have one significant digit either 670000 or 700000 is what the computer is looking for

*March 11, 2017*

**Chemistry**

the drops happen, but are not counted the fewer the drops to the endpoint, the lower the concentration of the unknown the concentration would appear to be lower than it actually is

*March 11, 2017*

**physics!**

velocity = circumference / period v = (2 * ? * 11.30 m) / 16.60 s plug it in and crank the crank

*March 11, 2017*

**pre calc**

1.7 = e^0.01t ln(1.7) = 0.01 t 100 ln(1.7) = t

*March 11, 2017*

**Math**

(300 * 200) - (280 * 180)

*March 11, 2017*

**Physics**

the centripetal acceleration is ... v^2 / r a) v^2 / r = g ... v^2 = 500 m * 9.8 m/s^2 b) his weight will be twice normal ... w = 2 * 80 * g

*March 11, 2017*

**physics**

95 km/h = 26.4 m/s 26.4 / 4.2 = stopping time (26.4 + 0) / 2 = ave stopping speed

*March 10, 2017*

**Math**

y varies inversely with x ... x y = k 25 * 5 = 125 ... x y = 125

*March 10, 2017*

**math**

the solution is the intersection of the lines

*March 10, 2017*

**Physics**

f = 1 / cycle time = 1 / (34.8 / 15)

*March 10, 2017*