# Posts by Scott

Total # Posts: 2,565

**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

**Physics**

A. t = 50 ft/s / 32.2 ft/s² B. the velocity is zero at the peak ... so the average ascending velocity is 25 ft/s ... the displacement is 25 ft/s multiplied by the time from part A C. the time is half of the time from part A ... the average velocity is (50 + 25)/2 ft/s...

**Algebra**

you are correct (-11)^2 would be 121

**Math**

W = H + 4 L = W + 8 = H + 4 + 8 = H + 12 A = 2H (W + L) = 2 H (2H + 16) 512 = 4 H² + 32 H 128 = H² + 8 H 0 = H² + 8 H - 128 solve for H, then substitute back to find W and L

**trigonometry**

11π / 12 corresponds to a 15º reference angle in Q II 15º is half of 30º use a half-angle identity to find the exact value

**Physics**

the man is twice as far from the fulcrum as the rock so the effort is half the weight of the rock

**PHYSICS topic is pressure**

it is the lowered PARTIAL PRESSURE of oxygen, coupled with the increased PP of carbon dioxide that causes problems

**PHYSICS topic is pressure**

a deep well allows for little air circulation and the components of the atmosphere can stratify to a certain extent oxygen (which we need to breathe) is not the densest component the noble (inert) gas, argon, makes up about 1% of air; and is the heaviest as already mentioned, ...

**SCIENCE**

see the physics question 3 above yours

**Maths Algebra**

b = g + 334 b + g = 572 substituting ... g + 334 + g = 572

**Trig**

a sine value of .5 means a 30º reference angle in Q III, the angle is ... 180º + 30º = x

**Maths Algebra**

3/5 = 24/40 1/4 = 10/40 1/8 = 5/40 1/40 is left for foot travel 1/40 j = 2 km ... j = 80 km

**Maths Algebra**

9 is 1/4 of 1/2 of the herd 1/8 h = 9

**Algebra**

<

**Math**

46 divided by 1

**Physics**

the kinetic energy of the ball at launch equals the gravitational potential energy at the peak ½ m v² = m g h v = √(2 g h) = √(2 * 9.8 * 20) m/s

**Trigo**

the length of belt that passes over the pulleys is the same 18 * 2π * 6 = 5 * 2π * r

**Science**

yes

**Math**

the force is proportional to the area 30 N / 50 cm² = f / 1500 cm²

**mathematics**

30000 = x [1 + (.12/12)]^(5 * 12) 32500 = y [1 + (.12/12)]^(7 * 12) 36000 = z [1 + (.12/12)]^(10 * 12) find x, y, and z and add them together log(3000) = log(x) + 60 log(1.01) log(3000) - [60 log(1.01)] = log(x) 10^[log(x)] = x

**maths**

12 is the common denominator for 6, 3, and 4 10/12 - 8/12 + 15/12 = 17/12 = 1 5/12

**Math**

3/5 men...so 2/5 women the difference (1/5) equals 12 5 * 12 = ?

**Maths**

torque = force * distance 200 Nm = f * .40 m

**PreCalc**

you want the sin⁻¹ function on your calculator sin⁻¹(0.65) = Θ = .7076 , 2.4340

**Math**

8+{4 x [(2+7) / 3]} = 20

**PHYSICS/SCIENCE**

a third as much as 15.0 g

**Math**

x² + 7x + 12 = 0 (x + 3) (x + 4) = 0 x = -3 , x = -4

**Physics/Science**

150 cal to take the water to 0º C 79.7 cal/g to freeze it

**Math**

c = 3.5 x + 10

**Math-Direct Variation**

x = k y 3 = k * 6 ... k = 1/2 x = 1/2 * 2/3 = 1/3

**probability statistics**

between means ... 4000 < n < 7000 3 choices for the 1st digit ... 4, 5, 6 8 for the 2nd digit 7 for the 3rd digit 6 for the 4th digit numbers = 3 * 8 * 7 * 6

**statistics**

there are 11 letters 3 of them occur twice possible arrangements equal ... 11! / (2! * 2! * 2!)

**Calculus**

velocity is dx/dt integrating gives position t/42 = dx/dt t/42 dt = dx integrating ... t²/84 = x = 100/21

**math**

there are 9C4 ways of selecting four printers there are 5C4 ways of selecting four good printers the probability is ... 5C4 / 9C4

**Science**

the simplified range equation is ... Rmax = v² / g ... 100 = v² / g ... 100 g = v² when an object is thrown straight up, the initial kinetic energy becomes gravitational potential energy ... ½ m v² = m g h ... v² / (2 g) = h combining the two ...

**math**

b + c = 45 / 2.5 = 18 kph b - c = 39 / 3.25 = 12 kph adding equations (to eliminate c) ... 2 b = 30 kph solve for b substitute back to find c

**chemistry**

a mole contains Avogadro's number of particles 5 moles = 5 * 6.02E23

**Geometry**

90º - a = (180º - a) / 5 450 - 5a = 180 - a 270 = 4a

**Algebra/Quadratic Functions**

the minimum lies on the axis of symmetry x min = -b / 2a = -(-200) / 2*2 = 50

**Calc**

f(x) = x^2+(1000-x)^2 ... = x² + 1E6 - 2000x + x² ... = 2x² - 2000x + 1E6 the minimum is on the axis of symmetry at x=500 ... the function increases from there so as x increases (below x=500), the function decreases f(0) = 0² + (1000 - 0)² = 1000²...

**Math calculus**

s.a. = 6 s² da/dt = 12 s ds/dt v = s³ ... 8 = 2³

**Maths**

M = 2R M + 11 + R + 11 + 3 = 75 Roy's dessert ... 11 + 3 = $14 3R + 25 = 75 ... R = 50/3 Roy's meal ... $50/3

**Science**

f = 1500 * g * .2

**maths**

4 (1 / 2 μf) = 1 / Ce Ce = 2 μf / 4

**Math**

d = h cot(32º) d - 8 = h cot(43º) 8 = h [cot(32º) - cot(43º)] h = 8 / [cot(32º) - cot(43º)]

**Math**

3/5 = 6/10 ... so there were 6 groups of boys the 2/5 of the class that were girls resulted in 2 groups of 1/5 each an aside ... the girls' groups were twice as large as the boys' groups

**physics**

don't know if significant figures are an issue but there are two in the data, and four in the result

**Science**

the horizontal velocity is the total velocity multiplied by cos(30º) at the topmost point, there is no vertical velocity ... so the K.E. is ... E cos²(30º)

**Algebra**

nancy starts with $50 more, but annie can save $5 more per week 50 / 5 = 10 weeks