# Posts by Scott

Total # Posts: 3,355

Physics
so it's a water cube? ice has too low a density

Biology question pH
pH is logarithmic a change of 2 in pH means a hundred times change in the concentration of H+ ... 10^2 = 100 10^4 = 10000

Precal
[ln(7) / 2] x = ln(5) - [ln(5)] x x = ln(5) / {[ln(7) / 2] + ln(5)}

Algebra
n + 2s = 57 n + s = 18 subtracting the equations will give you s substitute back to find n

Physics
look at the kinetic energy for rolling up ... the steeper the ramp, the faster the KE becomes gravitational PE same holds true for rolling down, except the energy goes in the other direction

math
FOIL the binomials -16 - 24i + 6i + 9i^2 ... i^2 is (?-1)^2 collect like terms -25 - 18i

Math
SA is proportional to the square of the height V is proportional to the cube of the height

Math
the volumes of the model engines are proportional to the cubes of the scale factors

Math
it saves having to write out a lot of zeros, reducing the chance for error (and writer's cramp) one digit to the left of the decimal point ... the magnitude expressed as a power of ten 371 = 3.71x10^2 ... or ... 3.71E2 ... E describes the exponent of ten .00263 = 2.63x10^-...

physics
watch your sig figs you're mixing g and kg also , water density is 1000 kg/m^3 ... or 1 g/cm^3 V = 3300 g / 2.75 g/cm^3 convert V to m^3 and use 9.81 for g ... Fb will be in Newtons

arithmetic progression
2[(5 * 3) + 10d] = (8 * 3) + 28d

Probability and Statistics
another binomial p (prefer A) = .85 = (P) p (not prefer A) = .15 = (N) (P + N)^19 = 19C17 P^17 N^2 ... = 171 * .85^17 * .15^2

Probability and Statistics
this is a binomial problem probability of hit (h) = .193 probability of no hit (n) = 1 - .193 = .807 at least 2 means not zero and not one (n + h)^7 = n^7 + 7 n^6 h... p(h ? 2) = .807^7 + (7 * .807^6 * .193)

Geometry
no figure?

math
looks good

maths
(4C3) * (5C3) * (6C3)

algebra math, 8th grade
the 1st number in the parentheses is the x-value (left/ right or horizontal) the 2nd number in the parentheses is the y-value (up/down or vertical) final position ... [(-2+1),(-5+3)]

physics
constant velocity (not accelerating), means the the thrust equals the resistive force

Algebra2
sorry you're stuck ... we can help need examples

physics
looks good

Freshman Algebra 1 Honors
p = 303146000 (1 + .0091)^(2017-2009) or ... p = 303146000 e^[.0091(2017-2009)] v = 125000 (1 - .15)^10

Science
molarity is moles of solute per liter 1L of solution has a mass of ... 1010 g mass of H2O2 is ... 1010 * .152 g divide H2O2 mass by H2O2 molar mass to find the molarity

physics
the ratio of the areas is the square of the ratio of the radii

Algebra I
I answered this before you start with -4 then add 3 , 2010 times -4 + 6030 is the 2011th term

precalculus
looks good

physics
moon's gravity provides the centripetal force for the orbit m v^2 / r = G M m / r^2 orbital velocity ... v = 2 ? (1500 + 550) * 1000 / (48 * 3600) r = (1500 + 550) * 1000 meters ... G = 6.67E-11 M = v^2 r / G kg

Math
4C2 ways to get two aces 52C2 ways to get two cards 4C2 / 52C2 = ?

math
use a table to find the z-score for the upper 15% cutoff score = 280 + [(z-score) * 20]

Math
210000 - 185000 = 25000 25000 / 20000 = 1.25 s.d. above the mean ... this is the z-score use a table to find the fraction above this z-score

physics

Algebra
gravity provides a force of attraction between masses a force acting on a mass causes it to accelerate the function [s(t)= -1/2 gt^2 + vt + h] describes the height (s) relative to time (t) of a mass (object) in freefall ... g is the gravitational acceleration ... v is the ...

Math
[(400 - 360) / 400] * 100%

Math
yes

Math
try moving the decimal point 1/2 = .5 = 50%

Algebra I
-4 + (3 * 2110)

Math
p is the population 5 yrs ago you do know how to work a calculator, yes?

Math
3104 = p (1 + .05)^5 log(3104) - 5 log(1.05) = log(p)

Math
line would go to the left Z values are less than 8

Math
yes

GEOMETRY
m?G = m?C 180º - m?B - m?C = m?A

Math
a + s = 450 200a + 150s = 14400 solve the system by using substitution or elimination

algebra
they each do a fraction of the task, based on their individual times ... the fractions sum to one (the whole task) t/21 + t/28 + t/48 = 1 ... LCD is ... 21 * 16 16t/336 + 12t/336 + 7t/336 = 336/336 35t = 336

physics
gravity provides the centripetal force m g = m v^2 / r ... v^2 = r g = 22 * 9.8 answer is in m/s

algrebra 2
g(x) substitutes for x in f(x) ... 2(4x + 2) - 2 = 8x + 2

Math
probability event not happening ... 1 - p

algebra
area = x * y x + 2y = 45 ... x = 45 - 2y substituting ... a = 45 y - 2 y^2 ymax = -b / 2a = -45 / (2 * -2) = 11.25 x = 22.5 a = 22.5 * 11.25 = 253.125

Intermediate Algebra
the marked-up price (m), is 33% more than the publisher's price (p) m = p + .33 p ... 75 = 1.33 p

algebra 1
if you solve the 2nd equation for y ... resulting in the slope-intercept form you will see that the slopes are negative-reciprocals of each other

algebra 1
two lines can intersect without being perpendicular ... like an X

Algebra I
B would be correct if it had a decimal point ... .63 the others aren't even close

geometry
check the naming of the angles ... the middle letter is the vertex ... ACB AND ACD can't be in the same triangle

Math
it takes her twice as long to go half as far so she walks a quarter as fast as she rides w = (d/2) / 2t = 1/4 d/t r = d/t

math
(60 * .6) + (x * 0) = (60 + x) * .5 (60 * .6) + (x * .3) = (60 + x) * .5

Physics
the net accelerating force is the difference in the weights (gravitational force) of the two masses a = f / m = (120 N - 80 N) / 20 kg find tension by looking at the smaller mass ... net force required for acceleration T - W = 8 kg * 2 m/s^2 ... T - 80 N = 16 N

Calculus
you used degrees, yes? 1051? implies radians ... so the answer would be ?

the angles sum to 360º 360 - 110 - 70 = 180 4n + 5n = 180 find n , then find the two angles (4:5)

Maths
(185 + 240) / (15 + 20) = S m/s 1000 m in a km ... 3600 s in an hr m/s * 3600 s/hr / 1000 m/km = km/hr

Calculus
continuous growth ... p e^(rt) 2.8E9 = 6E8 e^(300r) ln(28/6) = 300 r ... solve for r 2.5E10 = 6E8 e^(rt) ... solve for t

Math Help!!
y = -1/49 x the slope of the perpendicular is ... -(-1/49) = 49 the 1st derivative is the slope of the tangent ... dy/dx = 14x + 7 14x + 7 = 49 find x, then find y from the original function

physics
their brightness ratio is the ratio of the inverse of the square of their distances bP / bQ = (dQ / dP)^2

physics
f = m * a ... answer is in Newtons

Algabra
division by zero is undefined

physics
a. acceleration = speed / time ... 40 / 5.0 b. (average speed) * time ...[(0 + 40)/2] * 5.0

math
{[1 + (.2351 / 365)]^365} - 1

physics
it's an inverse square relationship B appears 16 times brighter ... 4^2

Algebra
6400 * [1 + (.08 * 9/12)]

math
3 in = 5 mi squaring ... 9 in^2 = 25 mi^2 a = (45/9) * 25 mi^2

Math
y + 5 = -2/5 (x + 3)

Algebra
i = ?-1 ... i^2 = -1

Algebra
(x + 1 - 4i)(x + 1 + 4i) x^2 + x + 4ix + x + 1 + 4i - 4ix - 4i - (4i)^2

Math
the area of the round pizzas is equal to the rectangular pizza 2 ? r^2 = 40 * 60 ... r^2 = 1200 / ? diameter = 2 r

Science
I think you are right lighter fish are less visible than darker fish in the clearer water

C(54,11) are duplicates

Math
arithmetic means that the difference between any two consecutive elements is always the same any two numbers next to each other always have the same difference

Algebra
16. b^2 - 4 a c = 144 ... a perfect square ... the roots (intercepts) are unequal integers 17. the equation of the axis of symmetry is the average of the intercepts ... a.o.s. ... x = (8 - 4) / 2

math
"so the answer is 9,4?" ... no Q = [(Mx + 9),(My + 4)]

math
Q is as far from M , as M is from P 9 in the x-direction ... 1 - -8 ... Qx = Mx + 9 4 in the y-direction ... 7 - 3 ... Qy = My + 4

math
the x distance is ... 18 - 2 = 16 2/5 * 16 = 32/5 = 6.4 Ax + 6.4 = 8.4 the y distance is ... 12 - 6 = 6 2/5 * 6 = 12/5 = 2.4 Ay + 2.4 = 8.4 partition point ... (8.4,8.4)

Maths
cross section ... (? / 4)[(do)^2 - (di)^2] volume = cross section * length mass = volume * density weight = m g

Algebra
the center of the circle is the average of the intercepts ... (1 - 7) / 2 = 4 ... center at (0,4) the radius is the distance from the center to one of the intercepts ... 7 - 4 = 3 the general circle equation is ... (x - h)^2 + (y - k)^2 = r^2 ... center at (h,k) , radius = r

Math
9 * 8 = 72 ... 72 + 5 = 77

Science
displacement means how far from where you start once around brings you back to where you start

Science - Physics
power = (weight * height * reps) / time watts = (50 * 9.8 * .5 * 40) / 60

algebra 1
slope = change in y / change in x

physics
angular ... 2.55 rad / 2.30 s

physics
one lap (circle) is 2? radians 5/2 * 2? radians in 3.0 min (180 sec) angular speed is rad/s or rad/min

Math
d/12 + 1/15 = d/10 - 1/10 ... 60 is LCD 5d + 4 = 6d - 6

Geometry
got the right slope point-slope ... y - 7 = -1/2 (x + 4) equation looks good

Chemistry
1. molar mass of Na is 23.0 g moles of Na = 31.5 / 23.0 moles of H2 is half of Na ... from reaction equation a mole of ANY gas is 22.4 L at STP 2. the equation is balanced theoretical is what you get if ALL the sodium reacts with oxygen to form sodium oxide 54.1/23.0 moles of ...

Science
traveling through a vacuum (outer space), kind of rules out convection and conduction

PHY
2 T sin(?) = m g 2 * T * sin(10.0º) = 50.0 * 9.81 answer is in Newtons

Math
(7/8)x - 9 = 5 7/8 x = 14

Algebra
2 = [1 + (.1 / 12)]^(12 t) ln(2) = 12t ln(12.1 / 12) [ln(2)] / [ln(12.1 / 12)] = 12 t

Algebra
times 1000 n ... 4234.3434... times 10 n ... 42.3434... subtract to cancel decimals 990 n = 4192 ... n = 4192/990 reduce the fraction

science
parallel means 0.2V across 2.0? current = voltage / resistance

Physics
1/2 m v^2 + m g h = 1/2 m V^2 1/2 m 72^2 + m 9.8 35 = 1/2 m V^2 72^2 + (9.8 * 70) = V^2

math
f = 1st mech , s = 2nd mech 10 f + 5 s = 1525 f + s = 200 solve the system using substitution or elimination

Physics
momentum is conserved total momentum = sedan + convertible (1200 + 1000) 16 = ... (1200 * 10) + 1000 v

Math
fill A fill C from A pour A into B ... one portion pour C into pail fill A fill C from A ... one portion in A pour C into pail ... one portion in pail

Math
16 oz per lb 1 3/4 lb for \$2.24 2.24 / (7/4) = ?