# Posts by Scott

Total # Posts: 2,570

**Physics**

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

**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

**Math**

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

**Math**

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

**chem**

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

**SCIENCE**

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

**Math**

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

**Physicd**

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

**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?)

**math**

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

**math**

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

**science**

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

**math**

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

**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

**Physical Science**

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

**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

**Math**

did you see the two sig fig part? 210000

**SCIENCE**

think you're right

**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

**math**

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

**11 grade / physics**

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

**Chemistry**

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

**Chemistry 11**

looks fine

**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

**Chemistry**

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

**Physics**

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

**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...

**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

**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

**Chemistry**

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

**pre calc**

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

**pre calc**

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

**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

**physics!**

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

**pre calc**

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

**Math**

(300 * 200) - (280 * 180)

**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

**physics**

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

**Math**

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

**math**

the solution is the intersection of the lines

**Physics**

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

**pre calc**

100 * 1/2 * 1/2 = 25 12 days = 2 half lives OR 1/4 = e^(12k) ln(1/4) = 12 k [ln(1/4)] / 12 = k ln(1/2) = k t t = ln(1/2) / {[ln(1/4)] / 12} = 6

**geometry**

it gives you the size of the interior angles of a regular polygon of n sides

**math**

90º is a quarter of a circle 1/4 * 1/4 = ?

**Algebra**

.9 x + 6.8 = .65 x + 7.3

**science**

the weight (force) of 50 kg is ... 50 kg * g ... g is the acceleration by gravity 200 * d = 50 * g * (2 - d)

**Pre calc**

pop = 900000 * k^t 800000 = 900000 * k^2 8/9 = k^2 ... k = 2?2 / 3 p = 900000 * (2?2 / 3)^5

**Math**

no ... is imaginary ... and irrational

**Math**

no ... is imaginary

**science**

a = f / m = 5224700 / 13500

**Algebra**

the corners are now three times farther from the origin just multiply each coordinate by 3

**Physics**

the beam weight is 50.3 N/m when Suki crosses a support to some distance (d), the equilibrium equation is ... (100.6 N * 1.00 m) + (595 N * d) ... = (251 N * 2.50 m) the distance from the end is ... 2.00 m - d

**Algebra2**

this is a circle, centered at the origin the domain and range are the same

**Math ASAP**

looks good

**Math**

180º - 65º - 65º = ?

**Calculus**

d = 2 r = 3 h ... r = 3/2 h v = 1/3 * ? * r^2 * h v = ?/3 * 9 h^3 / 4 dv = 9 ? h^2 dh / 4 dh = 4 dv / (9 ? h^2)

**Physics**

the incident angle is measured relative to the normal to the surface 90º - 60º = 30º

**Physics!**

.4 * 3000 = f (in Joules) 1) ma = 0utput / input = 3000N / 1000N 2) not enough info

**Math**

n, n+2, n+4 4(n+2) = n + n+4 + 2

**Physics**

that is the compression of the spring the more it's compressed, the greater the force

**Physics**

f = m a ... a = f / m a = (315 N * .15) / .00446 kg a is in m/s^2

**Physics**

ave speed = 1.4 rad/s stop time = 2 * ? * 60 / 1.4 acceleration = 2.8 rad/s / stop time ... negative ... wheel is stopping 30 * 2 * ? = 1/2 a t^2 + 2.8 t ... solve for t

**Precalc**

look at half the center 3rd it is a sector of the circle, with right triangles on either side the area of the sector is ... ? * r^2 * (?/360) ... ? being the central angle the combined area of the two triangles is ... r sin(?/2) * r cos(?/2) = r^2 tan(?/2) ? r^2 / 6 = r^2 [tan...

**math**

PEMDAS is the hierarchy of operations Parentheses...exponentiation ...multiplication...division ...addition...subtraction things in parentheses 1st ... 7^2 = 49 ...4 * 10 = 40 ...40 - 49 = -9 7 * -9 = -63 -63 + 4 = -59

**math**

.18 x + .40(10 - x) = .20 * 10

**Math**

like slicing bologna trees are cut on a "bias" to control the direction of fall

**Math - Trig**

Two buildings of equal height are 850 feet apart. An observer on the street between the buildings measures the angles of elevation to the tops of the buildings as 29° and 40°. How? high, to the nearest? foot, are the? buildings? I don't know how to set this up

**Trig**

the angle at the base of the pole is ... 90º - 8º the angle at the end of the shadow is the sun's angle the 3rd angle is opposite the 20 ft shadow use the law of sines to find the pole

**Physics**

the energy to lift the water is ... m g h = 10 kg * 10 m/s^2 * 10 m ... = 1000 J the kinetic energy of the water at delivery is ... 1/2 m v^2 ... = 1/2 * 10 kg * (10 m/s)^2 ... = 500 J 1500 J / s = 1500 watts = 1.5 kw

**math**

(1 - .75) * ? * 4 * r^2

**maths**

like the other one ... 5-12-13 tan = 12/5 sin = 12/13 cos = 5/13 cos(90 - ?) = sin (?) fyi ... holding down the 'alt' key while typing '233' will generate the '?'

**maths**

this is a 5-12-13 triangle cos = 5/13 tan = 12/5

**Chemistry**

don't know if sulfuric is moral or not ... however, it is diprotic (two H+) ?M = .16 * 25/17 * 1/2

**CIS**

1. you have 1GB and want to have 4 GB ... 2 open slots means a 1 GB and a 2GB module 2. 4 slots with 2GB each means max memory of 8GB

**Physic**

(a) w = m g (b) equal to weight (c) f = m a = 500 * 2.5 (d) moving (kinetic) (e) k = (7000 - 1250) / (m g)

**Physics**

some strike... impulse = change in momentum i = .34 kg (31.3 m/s - -6.18 m/s)

**Physics**

missed part (a) (a) voltage = [?(11.4/29.5)] * total R

**Physics**

I^2 = W / ? = 11.4 / 29.5 calculate I the resistors add in series power = I^2 * total R

**Math help plz?!!**

looks like your calculator is set on radians try again with degrees nearest hundredth is two decimal places

**Math! Help Hurry!**

same y-coordinates a vertical line length is the difference of the x-coordinates

**Maths**

think you are correct the question says p.a. (per annum) 58.7 is all four years ... divide it by 4

**maths trigonometry**

cos ? + 1 = 0 ... cos ? = -1 ... ? = ? tan ? - 1 = 0 ... tan ? = 1 ... ? = ?/4 , 5?/4

**Math(precalc)**

the logs are just (messy) numbers that you can distribute, add, subtract... [4 log(4)] x - 3 log(4) = ... [9 log(3)] x - 6 log(3) grind away...

**Algebra**

seven three with one top three with 2 top one with three top

**Physics**

e = (wavelength / c) * h c = speed of light h = Planck's constant

**math**

a square has FOUR equal sides 4 * 1/3(x+2) = 4/3 x + 8/3 = P 4/3 x = P - 8/3 4 x = 3 P - 8 x = 3/4 P - 2

**Biomechanics**

so what is her vertical velocity after one second? you found the correct acceleration

**Algebra, Math**

.3 x + [.1 (500 - x)] = .25 * 500

**math**

(x + 5)^2 + (y - 2)^2 = 676 plug in the points to check if they lie on the circle

**Science- Astronomy**

venus is closer to the sun and has a shorter "year" earth has a moon but venus has none

**science**

because the moon is between the Earth and the Sun the sunlight reflected off the moon, that we normally see, is pointed away from us this is when solar eclipses can occur

**Álgebra**

2 * [(8 * 14) + (8 * 10) + (10 * 14)]

**Math**

5C3 = 10

**Math**

inverse ... y gets smaller as x gets bigger x y = 10

**physics**

the KE of the bullet e = 1/2 * .02 kg * (150 m/s)^2 answer is in Joules

**SAT Math**

4/3

**Chemistry**

these values are negative logarithms of the concentrations so a bigger number means a lower concentration

**Science**

work = f * d = 60 * 2 = 120 J power = work / time = 120 / 10 = 12 W work is in Joules and power is in Watts

**homework**

36 m times 4 lengths per day times 7 days per week times 4 weeks

**Science**

the mass (in kg) multiplied by the gravitational acceleration (in m/s^2) gives the weight in N (Newtons) w = .0585 kg * 9.8 m/s^2 w = .04593 kg * 9.8 m/s^2 the g value is 2 sig fig, so that is what the answer will have