# Posts by Scott

Total # Posts: 2,313

**Physics**

k = f / e k1 e1 = k2 e2 e2 / e1 = k1 / k2

**chemistry**

call the 2nd gas B 3 g of B is half as many moles as 2 g of A B / A = 3 / 1

**Jar Marbles**

a) one of the five red marbles has the number 3 on it, so the probability is 1/5 b) two marbles have the number 1 on them, one red and one blue ... so the probability is 1/2

**Maths**

u = 2t - 6 10u + t = 10t + u + 9 substituting ... 20t - 60 + t = 10t + 2t - 6 + 9 solve for t, then substitute back to find u

**physics**

gravitational force follows an inverse-square relationship inverse of 1/8 is 8 ... 8 squared is 64

**math**

The Holy Father sent a courier from Rome to Venice, commanding him that he should reach Venice in 7 days. The most illustrious Signoria of Venice also sent another courier to Rome, who should reach Rome in 9 days. And from Rome to Venice is 250 miles. It happened that by the ...

**Physics**

the average velocity during braking ... (13.1 + 0) / 2 divide the stopping distance by the average velocity to find the time

**Math**

take out a common factor

**Algebra**

common factor 5x (x + 2)

**Chemistry**

the reaction equation is written in MOLES 2 moles NO plus 1 mole O2 yields ... 2 moles NO2 so 5 moles of O2 uses 10 moles of NO find the molar (formula) weight of NO, and multiply by 10

**Physics**

the delay time is down and back ... twice the depth

**Physics**

yes

**Physics**

how about 4 by 2.9 ...

**Physics**

time = √(2 * distance / acceleration) initial velocity = 2 (distance / time)

**Chemistry**

there are about 55.3 moles of water in a liter the mean (average) concentration of chloride ions will be twice the arithmetic average of the MgCl2 concentrations (two Cl- for each MgCl2) I would be tempted to disregard the 175 value as a "flier"...but that's up ...

**Science Check my work PLS**

#8 ... a range of 5 in the 3rd digit is fairly precise the accuracy is substantially flawed

**Science**

a = f / m = 3 / 1

**physics**

the period is related to the mass and the spring constant the amplitude is inconsequential

**physics**

momentum is conserved the 2nd (larger) piece moves in the opposite direction at 1/3 the speed

**physics**

P = m g h / t = 100 * 10 * 6 / 120 answer is in Watts

**Calculus II**

If f(x) - x cos (x), how many intervals would be needed to approximate with the Trapezoidal Rule with an error of E<.01?

**Math 115**

a million is a thousand thousand (276.5 / 3150.4) thousand per mi^2

**Physics**

Tn = d / 40 Ts = d / 60 Save = 2d / (5d / 120)

**Physics**

.6 g = v^2 / r

**Calculus**

f(x) = x^2 has a critical point (and a MINIMUM) at x=0 f(x) = (x^3 + 3x^2 - 4x - 12) / (x+2) ... has a critical point (and a "hole" at x=-2)

**College math**

p(white) = 9/24 = 3/8 p(green) = 8/24 = 1/3 p(w then g) = 3/8 * 1/3

**Math (Condensing logarithmic expression)**

ln{5^2 * [x / (x^2 + 1)^2]^3}

**ACT math**

h + s = 10 ... s = 10 - h 12 h + 14 s = 128 substituting ... 12 h + 14(10 - h) = 128 ... 12 h + 140 - 14 h = 128 ... -2 h = -12

**Physics**

gravitational potential energy becomes kinetic energy m g h = 1/2 m v^2 v = √(2 g h) = √(2 * 9.81 * 15.0)

**Chemistry**

the sulfite ion has a -2 charge Pb(SO₃)₂ the hydrogen phosphate compound is missing a subscript 4 Pb(H₂PO₄)₄

**algebra 2**

3/5 (∛5)^2

**Physics**

compressing 0 cm to 6 cm is equivalent to compressing 0 cm to 3 cm, and continuing to compress 3 cm to 6 cm although the compression lengths are the same for the two parts, the 2nd part takes more work because the resistance of the spring increases with compression 0 to 6 uses...

**Calculus**

points with the same x or y coordinate represent vertical or horizontal chords of the circle the perpendicular bisectors of the chords are diameters, and they give one of the coordinates of the center you can use the distance formula to find the other coordinate of the center ...

**math**

you don't show any of the data, but it's very likely that the line doesn't go through the origin (0,0) there is probably some base rental charge (represented by the intercept)

**Chemistry**

E = m g h ... h = E / (m g) h = 628 kJ / (70 kg * 9.81 m/s^2) 1 Joule = 1 kg m/s^2

**Physics**

the ball is uniformly accelerated by gravity average velocity = ... (final vel. + initial vel.) / 2 6.5 m / 3.1 s = (V fin + 0) / 2

**Math (calculus 3)**

the given height equation is incorrect ... the t^2 coefficient is -16, not -8 solve away...

**MATH**

try again when the bases are the same, just add the exponents 3^2 x 3^2 = 9 x 9 = 81 = 3^4 ... not 9^4

**MATH**

try again when the bases are the same, just add the exponents

**help plzz asap**

the trains are closing at 110 mph ... (50 + 60) t = d / r = 330 mi / 110 mph

**Physics**

the .410 coefficient means that the max acceleration is .410 g

**Physics - EMERGENCY PLEASE HELP**

v^2 / r = 5 g r = v^2 / (5 g) r = (288 km/h)^2 / 49 m/s^2 r = (80 m/s)^2 / 49 m/s^2

**Math**

Oops forgot one step Ignore my first answer Step 1.)5*15=x Step 2.)x*5=Answer

**Math**

Step 1.) 5*15=x Step 2.)x*4=Answer

**Math~ Algebra 1**

Thank You

**Math~ Algebra 1**

Two cars are traveling on the same highway. The first car is traveling at an average rate of 44mi/h. The second car leaves an hour late traveling at an average rate of 55mi/h. How long will the cars have traveled when the second car catches up with the first car?

**Math**

2 dived by 1/4= 8 banners

**Science**

the -256 C gas is hydrogen oxygen is -183 C they are both diatomic gases the volume of hydrogen (g) produced is twice the volume of oxygen (g)

**Algabra**

H < D < T H + 2 = D ... D + 2 = T 3 D = 2 T + 13 3 D = 2 (D + 2) + 13 = 2 D + 17

**Math**

draw a picture of the map for b they give you all the dimensions you need

**Math**

6 inches on the map equals 72 miles on the ground a. 1 inch equals 12 miles b. 2 inches on the map equals 24 miles on the ground

**Math**

L + P + N = 4050 L = P - 326 2 (L + P) = N L + P + 2L + 2P = 4050 L + P = 1350 (P - 326) + P = 1350 2 P = 1676

**physics**

the trains are closing at 50 kph (25 + 25) they start 150 km apart, so it takes them 3 hr to meet (and pass) the bird flies for 3 hr at 50 kph, so it flies 150 km

**physics**

the speed of sound in air is approximately 340 m/s the speed of light (from the flash) is approximately 3E8 m/s ... instantaneous for practical purposes so the distance to the bolt is ... 3 s * 340 m/s

**Biology**

if the dress absorbed red light, then red would not be reflected to your eyes ... the dress would not look red

**chemistry**

carbon dioxide is 32/44 oxygen by mass 3.70 g / (32 / 44)

**physical science**

weight is directly proportional to mass and gravitational acceleration ... w = m g w = 81.4 * (8.87 / 9.81)

**Physics**

f = m a m g - t = m a t = m g - m a = m (g - a) t = 2.45 (9.80 - 2.55) answer units are Newtons

**physics**

the free-fall equation is ... h = -4.9 t^2 + 12 t + Hb a. 0 = -4.9(3.4)^2 + 12(3.4) + Hb b. Tmax = -12 / (2 * -4.9) ... plug Tmax into the free-fall equation to find Hmax c. v = g(3.4 - Tmax)

**PHY**

h = 1.41 tan(34.7º)

**physics**

the increase in kinetic energy is from (equal to) the decrease in gravitational potential energy v^2 = 2 g h = 2 * 980 * 40 sin(.1 rd)

**Physics**

50 (5 + d) + 25 d = 200 (5 - d) 250 + 75 d = 1000 - 200 d 275 d = 750

**PRE-CAL**

2 = e^(11r) r = ln(2) / 11 1600 = P e^[10 ln(2) / 11]

**Maths**

a + b = 8 7 a^2 = 2 b^2 + 13 7 (8 - b)^2 = 2 b^2 + 13 448 - 112 b + 7 b^2 = 2 b^2 + 13 5 b^2 - 112 b + 435 = 0

**Physics**

from the general free fall equation 0 = -4.9 t^2 + 5 t + 98 v = -9.8 t + 5

**Physics**

see earlier post

**Ashley**

the distance equals the flight time multiplied by the horizontal component of the takeoff speed t = 2 {[s * sin(27.1º)] / g} d = t * [s * cos(27.1º)] 7.73 = 2 * s^2 * sin(27.1º / 2) / g

**Statistics**

see earlier submission

**Math**

p(not correct) = 1 - .797 p(at least one) = 1 - p(none) p(none) = (1 - .797)^3

**Chem**

g/ml * ml ---> g

**Physics**

one cycle (rotation) in 12 hrs (12 * 60 * 60) sec per cycle (1 / 43200) hz

**chemistry**

c - 44 = f f = (9/5 c) + 32 substituting ... c - 44 = (9/5 c) + 32

**precalc**

w^2 + (π/2) (w/2)^2 = 240 ft^2 w^2 [1 + (π/8)] = 240

**chemistry**

the ratio of NH3 to H2O is 4:6 or 2:3 NH3 / 2 = H2O / 3 NH3 = 2/3 * H2O 2/3 * 8 = ?

**math**

5 + 4i

**RPS**

6a + 5d = 6 ... a = 1 - 5d/6 (2a + d) (5a + 4d) = -80 ... 10 a^2 + 13 ad + 4 d^2 = -80 substitute for the value of a solve for d substitute back to find a

**math**

looks good

**physics**

looks like gravitational potential energy the energy equals the mass of an object, multiplied by the gravitational acceleration, multiplied by the height of the object

**Physics**

100 N * sin(45º) * 10 m = ? Joules

**Physics**

the height of the tree is ... 54 tan(30º) m

**algebra 2**

mary has a two hour head start she is 120 mi (2 * 60) ahead when tom starts tom catches up at 10 mph (70 - 60) it takes tom 12 hr (120 / 10) to catch up 12 hr from 8 am is 8 pm

**physic**

speed = wavelength * frequency so, the speeds are in the same ratio as the wavelengths sglass = sair (wglass / wair)

**SCIENCE**

you're multiplying 3 sf by 4 sf the result will have the smaller number of sig figs a trailing zero without a decimal point is not significant

**Math**

this is a Pythagorean triple ... 3-4-5 times 2 ... 6-8-10 x^2 + (x + 2)^2 = 10^2 2x^2 + 4x - 96 = 0 x^2 + 2x - 48 = 0 (x + 8) (x - 6) = 0 x = 6 ... x + 2 = 8

**Chemistry**

distributing on the right ... 3.6 v = 2.7 v + (2.7 * 4.9) subtracting 2.7 v ... .9 v = 2.7 * 4.9

**Chemistry**

How did the left side of the equation went from 3.6*V to .9V?

**Chemistry**

p₁ v₁ = p₂ v₂ 3.6 * v = 2.7 * (v + 4.9) .9 v = 2.7 * 4.9 ... v = 14.7 the evacuated flask means that no additional air was introduced into the system ... just a volume increase with a corresponding pressure decrease

**Chemistry**

A flask of known volume was filled with air to a pressure of 3.6atm. This flask was then attached to an evacuated flask of known volume and the air was allowed to expand into the flask. The final pressure of the air (in both flasks) was 2.7atm and the volume of the second ...

**physics**

a slingshot launches a rock straight upward at 25 m/s, how high does the rock go, how long is it in the air, what is the velocity and the acceleration of the rock at its highest point

**physics**

a greyhound is capable of running at 40 mph, how many meters could the greyhound run in 3 minutes at this speed, how many seconds would it take the greyhound to run 1 km at this speed

**Chemistry**

so the concentration of H⁺ from the HCl is ... 1 mole in 6 moles of water pH is based on moles of H⁺ per liter of solution water's volume is 18 mL per mole (based on the molar mass) so 6 moles is 108 mL so, [H⁺] = 1 mole / .108 L pH is the negative log of...

**Physics I - Modern**

the momentum is the product (multiply) of the relativistic mass and the velocity the relativistic mass is the rest mass multiplied by gamma (the relativistic "fudge factor") gamma = 1 / sqrt[1 - (v² / c²)] p = gamma * rest mass * v hyperphysics (web) is a ...

**math**

that is the number for all correct (or incorrect) see the answer to your other posted question

**math**

(a) it is a normal distribution (bell curve)n with the most likely score being half right (or wrong) you could plot the points using your binomial distribution from part (b) (b) the exponents in an individual term should sum to 15 only your last term does that otherwise, looks...

**Chemistry**

H₃BO₃ is triprotic (3 H⁺ per molecule) 29.15 * .025 = M * 3 * 25.0

**Algebra**

x (7 - 2x) (12 - 2x) = 33 4x³ - 38x² + 84x - 33 = 0 (9 - √15) / 2

**Physical science check my answers**

4. traveling a greater distance in the same amount of time means you went faster/slower?

**Chemistry**

a dm^3 is a liter two chloride ions per calcium chloride molecule .04 * .45 * 2

**solid mensuration**

π r² = 452 ... r = 12 the triangle formed by the chord and the radii from the ends has a central angle of 120º so 2/3 of the circle (240º / 360º), plus the area of the triangle; is the area of the larger segment

**Physics**

A. 239 = ½ * 3.7 * t² B. v = a t = -3.7 * t ... t is from part A