# Posts by Scott

Total # Posts: 2,432

**Physics**

the horizontal velocity is ... 31 m/s * cos(60º) the vertical velocity is ... 31 m/s * sin(60º) + ... 3.4 s * -9.8 m/s^2 add the two component vectors ... a^2 + b^2 = c^2

**problem solving**

s = m - 8 m - 6 = 3(s - 6) = 3 s - 18 m - 8 = 3 s - 20 susbstituting ... s = 3 s - 20 ... 20 = 2 s

**Physics**

height = 1/2 g t^2 + Vo t + Ho 0 = -4.90 * .750^2 + Vo * .750 + 4.80

**Physics**

the difference in total energy (kinetic plus potential) at the base and the top; is the energy input from the engine the ascent time is the average speed, (top + bottom) / 2; divided by the 4.40 km distance energy / time equals power your answer has 5 sig figs. but all the ...

**Physics**

energy = m g h = 73.0 * 9.81 * 420 time = 60 * 15 + 10 power = energy / time

**physics**

his weight plus the centripetal force must equal 1170 N 83.0 [g + (v^2 / r)] = 1170 v^2 / 18.0 = (1170 / 83.0) - 9.81

**physics**

pulling at an angle reduces the frictional force (by reducing the normal force) so the frictional force is ... .42 * {(85 * g) - [F sin(38º)]} the block is in equilibrium when the frictional force equals the horizontal component of the pulling force ... F cos(38º) ...

**Math**

(n / 3) - 7 = 0 n / 3 = 7 n = 7 * 3

**College Algebra**

y = a b^x 8 = a b^0 ... a = 8 2.4 = 8 b^1 ... .3 = b y = 8 * .3^x

**MATH**

division by zero is a no-no ... even 0/0 so the 2nd and 4th are undefined

**Algebra**

Q = 5 * 2^(S + 4)

**College Algebra**

5 * 1.083^13

**physics again**

the water velocity increase is due to the change in gravitational potential energy 1/2 m 3.00^2 - 1/2 m 2.07^2 = m g h 3.00^2 - 2.07^2 = 2 g h the kinetic energy of the jump is converted to gravitational potential energy 6.26^2 = 2 g h the max waterfall is the sum of the two ...

**physics**

the average speed over the interval is (3.00 m/s + 5.60 m/s) / 2 = 4.30 m/s 2/3 of its length is 1.00 m so the time of the interval is ... 1.00 m / 4.30 m/s the change in speed is ... 5.30 m/s - 3.00 m/s acceleration is ... speed change / time

**Physics**

dx = (14 t - 32) dt x = 7 t^2 - 32 t + c 25 = 7 (3^2) - 32 (3) + c 25 = 63 - 96 + c ... 58 = c x = 7 t^2 - 32 t + 58

**physics**

gravity is the centripetal force keeping the satellite in orbit g = m a = 76 kg * .63 m/s^2

**physics (super hard)**

the centripetal force at the top of the circle equals gravity v^2 / r = g v = √(g r)

**math**

a. v = 1/3 * pi * r^2 * h b. the base radius is 4 and the height is 3, so the slant height is 5 (3-4-5 triangle) the 5 is the radius of the circle of which the area of the cone is a segment ... the area of the circle is...25 pi the area of the cone is...4/5 * 25 pi

**math**

7 is the most likely outcome using distinguishable dice, there are 36 possible outcomes ... each of the six faces on a die can pair with the six faces on the other die ... 6 * 6 = 36 twelve of those outcomes result in a sum of 7 ... one third of the rolls

**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