# R_scott

Most popular questions and responses by R_scott-
## Statistics

the z-score of a sample is the number of standard deviations its thickness is from the mean thickness calculate the z-scores , then use a z-score table to find the probabilities

*posted on April 21, 2019* -
## Physics

r1 = [(r1 + r2) * r3] / (r1 + r2 + r3) plug in values and solve for r3

*posted on April 21, 2019* -
## Physics

2Ω in series with 3Ω is equivalent to 5Ω so the two parallel branches have the same resistance and current current = voltage / resistance

*posted on April 21, 2019* -
## science

2/3 * Dw = 1/2 * D?

*posted on April 20, 2019* -
## algebra

h = -1/2 g t^2 Vo t + Ho g is gravitational acceleration ... 32 ft/s^2 Vo is initial velocity .. 4 ft/s Ho is initial height ... 0

*posted on April 20, 2019* -
## Chemistry

heat lost by silver = heat gained by water heat change = mass * specific heat * temperature change

*posted on April 19, 2019* -
## Science

mass = weight / g

*posted on April 18, 2019* -
## math

looks good

*posted on April 18, 2019* -
## Physics

A) k = m g / x = 5.0 * 9.8 / .20 N/m B) find the work done (energy) in stretching the spring from .20 m to .80 m ... 1/2 k x^2 ... for each position the work is energy stored in the spring ... when the mass is released, the stored energy accelerates it

*posted on April 18, 2019* -
## Math

85 kph * sin (45º) = 550 kph * sin(Θ) Θ is the angle west of north

*posted on April 18, 2019* -
## Stats

so close to zero that you couldn't tell the difference ... unless, of course, you mean seconds instead of minutes 110 seconds is one second above one standard deviation from the mean find the z-score (number of standard deviations from the mean) ... and

*posted on April 17, 2019* -
## chemistry

P1 * V1 / T1 = P2 * V2 / T2 change ºC to ºK and plug in the values

*posted on April 17, 2019* -
## physics

force (weight) is the product (multiplication) of the pressure and the area

*posted on April 17, 2019* -
## Biology

"b" indicates an "x" chromosome carrying the recessive the father is ... xY , and the mother is ... xX the Punnett square gives ... xx , xY , Xx , XY ... all with equal probability xx - color blind female xY - color blind male Xx - female "carrier" - has

*posted on April 17, 2019* -
## math

s * (single game price) < (box season game price) dividing ... s < (box season game price) / (single game price)

*posted on April 17, 2019* -
## math

4 w + 3 b = $10.94 ... 8 w + 6 b = $21.88 3 w + 6 b = $11.28 solve the system ... elimination looks good

*posted on April 16, 2019* -
## math

henry2 20*10^18 ≠ 20^18

*posted on April 15, 2019* -
## Calculus

4 s + L = 112 ... L = 112 - 4 s v = s^2 * L = s^2 (112 - 4 s) = - 4 s^3 + 112 s find the local max v

*posted on April 15, 2019* -
## math

2^18 * 10^18 ... 2^8 * 2^10 * 10^18 ... 256 * 1024 * 10^18

*posted on April 15, 2019* -
## Science

Kaitlyn (and you) are both in error that's one down and three to go

*posted on April 15, 2019* -
## Math

π * r^2 = 188

*posted on April 15, 2019* -
## Technology

people's ideas ... things that are patented or copyrighted devices, software, music, movies, etc

*posted on April 15, 2019* -
## Science

wavelength and frequency are inversely related frequency and energy are directly related (Planck equation) gamma rays are high energy ... nuclear explosions are a source

*posted on April 15, 2019* -
## Physics

120 * (2850 / 95)

*posted on April 15, 2019* -
## Physics

momentum is conserved ... Mw * Vw = Ms * Vs the squid expels water equal to half of its own mass so the squid's velocity will be half of the water's velocity

*posted on April 15, 2019* -
## Physics

wavelength = speed / frequency

*posted on April 14, 2019* -
## physics

forces in opposite directions subtract from each other so the "effective forces here are ... 6N north and 2N east magnitude ... √(6^2 + 2^2) direction ... [arctan(2 / 6)] east of north

*posted on April 14, 2019* -
## BASIC TECHNOLOGY

in the gear system ... teeth * rotation speed = constant

*posted on April 14, 2019* -
## physics

remember to deduct the work done by the wind 63 m * 200 N * cos(20º)

*posted on April 14, 2019* -
## math

each year, the amount remaining is 76% of the previous year ... 100% - 24%

*posted on April 14, 2019* -
## Science

read the 1st sentence ... then try again

*posted on April 12, 2019* -
## Math

1st one needs work p v = k ... as volume goes up , pressure goes ?

*posted on April 12, 2019* -
## math

h + t + u = 9 2 t = h + u solve for t

*posted on April 12, 2019* -
## Math

1470 = [s - (s / 8) - (7s / 24)] / 4 solve for s (salary)

*posted on April 12, 2019* -
## Physics

a) f * d = 1500 N * 3 m = 4500 J b) 4500 J - m g h = 4500 J - (350 kg * 9.8 m/s^2 * .81 m)

*posted on April 12, 2019* -
## Calculus

n = .abcabcabc… multiplying ... 1000 n = abc.abcabcabc… subtracting ... 999 n = abc dividing ... n = abc / 999 curious as to which answer your teacher thought was correct

*posted on April 11, 2019* -
## math

there are 58 total pieces (20 + 38) ... what fraction are pins?

*posted on April 11, 2019* -
## Math

let n equal ones digit and t equal tens digit t + n = 10 10 t + n + 54 = 10 n + t solve the system of equations ... substitution looks like a good method

*posted on April 11, 2019* -
## algebra

1500 * (1 + .12)^7

*posted on April 11, 2019* -
## Chemistry

p v = n r t convert ºC to ºK ... dm³ = L use the value of r with the correct units solve for n ... moles of chlorine ... remember , chlorine gas is diatomic

*posted on April 10, 2019* -
## Math

looks good

*posted on April 10, 2019* -
## physics

try googling Hooke's law

*posted on April 10, 2019* -
## Physics

momentum is conserved ... but you need the mass of the truck to give an exact answer

*posted on April 10, 2019* -
## chemistry

6.2 mol / 1.35 mol/L

*posted on April 10, 2019* -
## Physics

v * 9.0 = 27.0 + (v * 1.2)

*posted on April 9, 2019* -
## Algebra

find the slopes of the lines parallel lines have the same slope perpendicular lines have slopes that multiply to -1

*posted on April 8, 2019* -
## math

move the decimal point to the right, until it is on the right of a non-zero digit the number of places the decimal point is moved, ... is the negative exponent of ten in the scientific notation

*posted on April 8, 2019* -
## Math

[5 + 5 + 2(t - 1)] * t/2 = 480 (4 + t) * t = 480 t^2 + 4t - 480 = 0

*posted on April 8, 2019* -
## math

try it ... y can be any value

*posted on April 7, 2019* -
## pre-calculus

center of wheel is 36m high ... (70 / 2) + 1 how much time >8m above center? draw a sketch ... diameter is horizontal at 36m ... 8m perpendicular from diameter to edge of wheel ... sine of central angle is ... 8 / 35 180º plus twice central angle is

*posted on April 7, 2019* -
## physics

find the volume of water per second ... a cylinder with a 7 cm diameter and a 33 m length ... convert to mass of water find energy (work) ... work = m g h work / time = power ... Joules / sec = watts

*posted on April 7, 2019* -
## Math - Plz help!!!

perimeter is two lengths plus two widths ... P = 2 L + 2 W The length is 2.3 meters longer than the width ... L = W + 2.3 ...substitute for the length 53 = 2 (W + 2.3) + 2 W = 4 W + 4.6 solve for W , then substitute back to find L

*posted on April 7, 2019* -
## Math

divide the 1st order terms' coefficients by 2, and square the results x^2 - 4 x + (-4/2)^2 + y^2 + 6 y + (6/2)^2 = (-2)^2 + 3^2 (x - 2)^2 + (y + 3)^2 = 13

*posted on April 6, 2019* -
## Math

1/2 * 1/2 * 1/2 * 1/2 = ?

*posted on April 4, 2019* -
## Math

each flip is an independent event ... with the probability of heads being 1/2 the probability of multiple independent events is ... the product of their individual probabilities

*posted on April 4, 2019* -
## Science Help

all the planets have elliptical orbits ... with varying amounts of eccentricity (elliptical-ness) the eccentricity of the Earth's orbit is very low ... the orbit is very close to circular

*posted on April 4, 2019* -
## Chem

{2.32 / [molar mass Al(OH)3(s)]} * 3 = moles (OH⎺) each mole of OH⎺ needs one mole of HCl to neutralize it

*posted on April 4, 2019* -
## Calculus

i refer you, again, to ... x^2 + y^2 = r^2 1^2 + (-√3)^2 = 1 + 3 = 4 = r^2 only one answer fits

*posted on April 4, 2019* -
## physics

umm ... the level started at 12 cm volume = (14 - 12) * 10 * 10

*posted on April 4, 2019* -
## Calculus

x^2 + y^2 = r^2

*posted on April 4, 2019* -
## Physics

angular momentum is conserved angular momentum = moment of inertia * rotational speed

*posted on April 4, 2019* -
## math

by inspection , 15 is the average of 20 and 10 ... so, equal amounts of the two with algebra ... .20 x + .10(1200 - x) = .15 * 1200

*posted on April 4, 2019* -
## Science

find the flight time ... 0.62 = 1/2 g t^2 use the time (t) to find the horizontal distance ... d = 0.61 t

*posted on April 3, 2019* -
## science

the force is inversely proportional to the square of the distance

*posted on April 3, 2019* -
## physics

frequency is proportional to the √ of the tension

*posted on April 3, 2019* -
## Probability

let a = k3 , b = k5 , c = k7.50 b = 3 a c = b + 500 3 a + 5 b + 7.5 c = 42225 substituting ... 3(b / 3) + 5 b + 7.5(b + 500) = 42225 solve for b , then substitute back to find a and c

*posted on April 2, 2019* -
## math

r^(5 - 2) = 48 / 6 ... r^3 = 8 ... r = 2 An = 3 * 2^(n-1)

*posted on April 2, 2019* -
## chemistry

500mL of 3M HCl contains 1.5 moles of HCl so 129.31 mL of the 11.6 M acid is needed acid is added to water (NOT vice versa) using a volumetric cylinder, add the necessary acid to 350 ml of water ... then add more water to make the 500 mL of solution

*posted on April 1, 2019* -
## math

14^2 = ? ? / 90 = !

*posted on April 1, 2019* -
## Science

more work needed are you clear on homozygous vs heterozygous?

*posted on April 1, 2019* -
## physics

the hot water looses heat , and the bath water gains heat [80.0ºC - (final temp)] * 2.00 kg = [(final temp) - 27.0ºC] * 20.0 kg

*posted on April 1, 2019* -
## Physics: Newton's Second Law

use ... f = m a ... on the 3 kg car ... the f is the tension

*posted on March 30, 2019* -
## math

his weight is not a factor the free fall equation is ... h = -1/2 g t^2 + Vo t + Ho ... h is height , g is gravitational acceleration ... Vo is initial velocity , Ho is initial height h = 0 at the bottom , g = 32 ft/s^2 0 = -16 t^2 + 0 t + 5996 solve the

*posted on March 29, 2019* -
## science

energy = mass * (specific heat) * (temperature change) 800 J = 1 kg * (specific heat) * (30 ºC - T) there are many types of glass , each with is own specific heat ... find a workable value and use it ... make sure the units include Joules and ºC

*posted on March 29, 2019* -
## Accounting

(final amount) = (initial amount) * [1 + (interest rate)]^(years) ... = 800 * (1 + .08)^3 gain = final - initial

*posted on March 28, 2019* -
## Physics

1/9 of the copper's mass is "supported" by the water tension = 8/9 * g * 0.5 kg ... Newtons

*posted on March 28, 2019* -
## pre algebra

the function rule tells you how to get y from x x is increasing by 2, while y decreases by 1 ... this means the slope is -1/2 try some values to see if you can find the y-intercept

*posted on March 27, 2019* -
## physics

mass1 * (distance1 from CG) = mass2 * (distance2 from CG) distance1 + distance2 = 0.20 m

*posted on March 27, 2019* -
## physics

the black ball's initial momentum is now shared by both balls find the initial momentum (it is conserved) use the combined mass to find the new velocity

*posted on March 27, 2019* -
## math

the 8 hours of overtime resulted in 12 hours pay normal rate = 650 / (40 + 12)

*posted on March 26, 2019* -
## Math

given??

*posted on March 26, 2019* -
## Math

plug in the x and y values for each pair , and see which one works ... makes the equation true

*posted on March 26, 2019* -
## Chemistry

6M means 6 moles in one liter of solution 100ml is a tenth of a liter , so you use 6/10 of a mole of NaOH measure .6 moles of NaOH ... molar mass * .6 use a graduated container ... add about 60 or 70 ml of water ... add NaOH and dissolve completely ... add

*posted on March 25, 2019* -
## Chemistry

find the number of moles ... mass / molar mass ... this is n p v = n r t ... choose the proper r value based on the units ... ºC, atm ... you will probably have to convert ºC to ºK

*posted on March 25, 2019* -
## math

let x = smaller , y = larger y - x = 3 ... y - 3 = x y^2 + x = 417 solve the system

*posted on March 24, 2019* -
## Math

look at the 1st one again

*posted on March 24, 2019* -
## Science

assign the initial path of A as either the x or y direction find the initial momentum of A in the x and y directions ... then, find the final momentum of A in the x and y directions ... the difference, in x and in y, is the momentum imparted to B use B's x

*posted on March 24, 2019* -
## Physics

find the initial momentum of A in the x and y directions ... then, find the final momentum of A in the x and y directions ... the difference, in x and in y, is the momentum imparted to B use B's x and y momenta to find its final velocity

*posted on March 24, 2019* -
## Science

google ... how-do-you-calculate-freezing-point-depression

*posted on March 22, 2019* -
## math/pre-calc

tmax lies on the axis of symmetry of the parabola ... -b / 2a ... -100 / (2 * -4.9)

*posted on March 22, 2019* -
## Science

a few need rework ... gravity seems to be a theme here Tides are caused by A) gravity. B) heat. C) waves.

*posted on March 22, 2019* -
## Physics

final energy = initial energy + energy from gravity 1/2 m Vf^2 = 1/2 m 16.0^2 + (m * 9.8 * 27.5) Vf^2 = 256 + (2 * 9.8 * 27.5)

*posted on March 21, 2019* -
## Math

yd^3 = 27 ft^3 3 ft^3 / (4 * 27 ft^3) = ?

*posted on March 20, 2019* -
## Precalculus

9/365 * 2 * π * 93 million

*posted on March 20, 2019* -
## math

1 foot by 1 1/2 foot

*posted on March 20, 2019* -
## Math

find the rate of fall ... (change in altitude) / (change in time) ... this is the slope of the line ... y = m x + b plug in one of the time/altitude points to find the y-intercept (b)

*posted on March 20, 2019* -
## Quadratics

you have three equations and three unknowns ... the unknowns are ... a, Vo, and So 144 = 1/2 a (.5^2) + Vo .5 + So 152 = 1/2 a (1^2) + Vo 1 + So 128 = 1/2 a (2.5^2) + Vo 2.5 + So solve the system for a, Vo, and So ... use the resulting equation to find max

*posted on March 20, 2019* -
## Math- Algebra

revenue = (500 - 20 x)(45000 + 5000 x) ... = 22500000 +1600000 x - 100000 x^2 xmax = -1600000 / (2 * -100000)

*posted on March 20, 2019* -
## Math

L + 2 W = 120 ... L = 120 - 2W area = L * W = (120 - 2W) * W = 120 W - 2 W^2 the maximum is on the axis of symmetry ... -b / 2a Wmax = -120 / (2 * -2) substitute back to find Lmax

*posted on March 20, 2019*