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Posts by scott

Total # Posts: 2,489

math
if 2 in equals 75 ft, then 8 in equals 4 times 75 do the same conversion for 3 in area of the park is length times width

precal 2
2000 ft down the mountain is the 6º angle so his distance to the mountain is ... d = 2000 ft / tan(6º) the mountain above 2000 ft is ... h = d * tan(20º) = 2000 * tan(20º) / tan(6º)

Math
for two unknowns (m and n) you need two unique equations for a solution since there is only one complete equation ... the 2nd equation must be similar it seems that the 9 may be a typo ... probably a 6 instead 6m + 3n = 3 (2m + n) = 21

math
(80 - 67) / 8

math
12000 [1 + (.03 / 4)]^(7 * 4)

Physics
the c-o-m is between the c-o-m of the stick and the c-o-m of the stone the centers of mass for the stick and the stone are in their physical centers using some distance (d) from the center of the stick toward the center of the stone ... 2.5 * d = 10 * (40 - 18/2 - d) find d...

Math
the LCM for 15 and 20 is 60 every 60 minutes

physics
potential energy --> kinetic energy --> heat energy energy = m g h (in Joules) energy / specific heat = temp change A) and B) look like the same thing ... energy

Algebra
he drives 220 mi on 5 gal ... 44 mi/gal ... slope is the car's MPG miles on remaining fuel is the range of the car ... range is DEPENDENT on gallons of fuel gallons on x-axis ... range on y-axis no fuel means no range ... both intercepts are zero (the origin)

algebra
n/2 - 16

Physics
x-component ... 3.50 m * cos(145º) y-component ... 3.50 m * sin(145º)

slope-intercept equation
5y = 2x - 10 ... y = 2/5 x - 2 negative-reciprocal slope, same y-intercept y = -5/2 x - 2

math
72 / 60 = 1.2 = ? %

math
80 * 1.12 = ?

Chemistry
atomic mass ... 106.4 moles per ml ... 12.0 / 106 ...OOPS... 6.02E23 * (12.0 / 106) * 5.89E-23

Chemistry
atomic mass ... 106.4 moles per ml ... 106 / 12 6.02E23 * (12.0 / 106) * 5.89E-23

math
so ... replacement or not?

math
re Damon's answer after the 1st card is drawn, that suit has fewer cards than the other three suits ... the probability is not 1/4 it is 12/51 but his logic works

math
number of same suit pairs ... 4 * 13C2 number of pairs ... 52C2 probability ... 4 * 13C2 / 52C2

science
momentum is conserved 10 * 1.5 = (90 + 10) * v

physics
4.18 * (50.0/13.0) * [(90.0 - 87.0)/(90.0 - 30.0)]

Math
1 / (d + 1) = (d + 1) / (5d + 1) 5d + 1 = (d + 1)^2 ... d^2 - 3d = 0 ... d = 3 An = 3n - 2

Chem
each mole of zinc produces a mole of hydrogen gas a mole of gas occupies 22.4 L at STP

physics
it's half the distance, so it should be twice the weight

College Physics
1/2 k x^2 = 1/2 m v^2 ... k x^2 = 4.0 * 0.70^2 = 1.96 k x = 12 dividing equations ... x = 1.96 / 12 substitute back to find k

Little star
m g h = 1/2 m v^2 ... h = v^2 / (2 g) = 200 / g 1/2 g t^2 = 200 / g ... t = 20 / g t is half of the time of flight

MATH
4 cm x 4 cm x 7.5 cm

math
204 / (9/4)

math
this is binomial ... collect or not collect 15C11 * .6^11 * .4^4

math
A = B / 4 B - 6 - 12 = A + 12 ... B = A + 30 solve the system

math
D1 + D2 + D3 = 1274 D1 + 70 = D2 D2 + 84 = D3 solve the system

physics
avg vel is 5 m/s (Va) during .2 s passage, accel (A) is ... .2 * g find vel at top of window .. Vt = Va - (A / 2) find fall time (Tf) to top of window ... Vt / g drop distance is ... 1*2 * g * Tf^2

physics
v^2 / r = 5 g v = ?(5 * 9.8 * 450)

Math
4 w + 2 k = 78 w + k = 35 solve the system for coWs and chicKens

math
find two perpendicular lines from the three points by finding the slopes between the three pairs ... that is one corner ... you are looking for the opposite corner ... use the slopes from the ends of the sides to find the missing point this should be very simple by using graph...

Science
m * g * h ... answer is in Joules

math
21C3 / 26C3

college physics
free-fall time (t) ... 81.9 cm = 1/2 g t^2 horiz velocity = 36.5 cm / t vert velocity = g t the velocity is the resultant of the horiz and vert components

college physics
time in air (t) ... 56.3 m / 29.5 m/s height of bldng ... 1/2 g t^2

Math
(t / 3) + 3 = t / 2

maths
s = smaller , r = longer s + 17.5 = r r / 3 = 3 s / 4 ... 4 r = 9 s solve the system

Math
(y^2 + 8)^2 = 79 y^2 = -8 ± ?79 y = ± ?(-8 ± ?79)

geometry
the ground and the height of the helicopter form two sides of a right triangle a line from the copter to the accident forms the hypotenuse the angle between the vertical and the hypotenuse is ... (90º - 10.2º) for one accident ... and (90º - 8.7º) for the ...

Maths
w + d = 45 w - 5 = 6 (d - 5) solve the system for w and d the answer is (w - d)

maths
1.89 / 1.8

science
mass / volume

Maths
2 * 3,41 * 25 * 50

physics
one inch equals 2.54 cm a square yard is 36^2 square inches a square meter is 100^2 square cm $18.95 * 100^2 / (36 * 2.54)^2

Geometry
a rectangle is a parallelogram with supplementary opposite angles (and congruent adjacent angles) a square is a rectangle with equal sides

physics
average velocity is ... wo / 2 time to stop is ... rev / vel = 2 X / wo acc = vel / time = wo^2 / (2 X)

Physics
weight minus vertical pulling component ... Fn = 300 - 100 sin(35º) horizontal pulling component divided by normal force ... [100 cos(35º)] / Fn

Pre-calculus
two values ... going up and coming down 4 = 1 + 9 t - 5 t^2 ... 5 t^2 - 9 t + 3 = 0 use quadratic formula to find t

Math
2/8 * 16 = ?

physics
100^2 + 50^2 = v^2 ? is the angle East of North tan(?) = 50 / 100 = .5

physical science
mass * .227 * (15.0 - 10.0) = 543 answer is in grams

Math
10 u + t = 10 t + u + 45 9 u - 9 t = 45

Number theory
2^9 = 512 2^5 = 32 2^2 = 4 2^1 = 2 1000100110

Maths
the angles are supplementary (sum to 180º) 2x - 8 + 3x - 7 = 180

Science
K.E. = P.E. 1/2 m v^2 = 36 ... v^2 = 36

Science
a Newton per square meter is a Pascal 16 N / 16 cm^2 = 1 N / cm^2 = 10 kPa

Physics, Calculus
flying at 250 kph with a 50 kph cross wind 250 is the hypotenuse the third leg (speed along heading) is ... ?(250^2 - 50^2) the angle (?) between the ground bearing and the flight bearing ... sin(?) = 50 / 250 ... towards N

Chemistry
the initial acid molarity is ... [HA] = .112 * (22.32 / 25.00) = 0.100 [H+] = 10^(-2.87) = .00135 ... this is also [A-] Ka = [H+][A-] / [HA] = .00135^2 / (.100 - .00135) remember ... the initial molarity changes because of the dissociation

Math
if it were only 500 students; three pencils each is 1500 pencils looks like Amy calculated two pencils each

math
a line from the origin, through the center of the circle, intersects the circle at the nearest and farthest points the center of the circle is (6,2) find the equation of the line, then substitute into the circle equation to find the intersection points

Math
15000 = x [1 + (.03 / 2)]^(8 * 2)

physic
the 4200 should be Joules, NOT kJ

Algebra
multiply by [(x-2)(x+1)] ... common denominator [x(x+1)] + [(x-1)(x-2)] = (x-2)(x+1) multiply and collect like terms you'll be solving a quadratic equation

Physics
the average speed while stopping is ... (20 + 0) / 2 = 10 m/s t = d / r = 4 cm / 10 m/s = .004 s

Physics
f = m a ... 2000 = 800 * a ... a = 2.5 m/s^2 it takes 8 s to stop ... 20 m/s / 2.5 m/s^2 average velocity during stop ... (20 + 0) / 2 = 10 m/s ... sorry, pooch ...

math
100 MJ/s e = m c^2 ... 1E8 = m * (3E8)^2 m = 1.1E-9 kg multiply by seconds in a day

physics physics
f = m a ... twice both ... 10 = (5.0 + 2.0) * a tension ... t = 2.0 * a ... a from 1st calculation

Math
869374521

math grade one
two tens ten twos four fives five fours

Geometry
adjacent angles of a rhombus are supplementary ... they add to 180º opposite angles are congruent

Physics 11
moving time = fixed time * dilation factor 0.50 = t * 0.474974 not sure why you had division, not multiplication

Physics 11
remember the twins paradox? one stays on Earth, the other goes on a high speed (close to c) trip the one on Earth grows old, but when the traveler returns, he is still young time passes slower in the high speed reference frame so the beats will be wider spaced for Tamara

math
a = 1st term A.P. ... d = common difference 10 a + 45 d = 85 ... 2 a + 9 d = 17 (3a + 3d) / (4a + 6d) = (4a + 6d) / (8a + 28d) two equations and two unknowns

pre-calculus
8y = -(x^2 + 6x - 7) = -(x^2 + 6x + 9) + 16 y = -1/8 (x + 3)^2 + 2 ... vertex form -1/8 ... opens downward vertex is (-3,2) ... midway between focus and directrix focus is (-3,0) axis of sym ... x = -3 directrix is ... y = 4

Physics
coefficient of friction needed

Calculus
?/2 is 90º on the unit circle ... tan = y/x at 90º, x = 0 dividing by zero gives the infinite limit depending on the direction of approach to ?/2, the sign of the limit can be +/-

mathhelop
let x = number of hotdogs sold let s = sell price of hotdog let c = fixed operating costs p = profit p = x s - c substitute to find s and c 100 = 90 s - c -30 = 25 s - c adding equations ... 130 = 65 s ... 2 = s 100 = 90 * 2 - c ... 80 = c p = 2 x - 80

Math
ones ... >7 and 4n ... 8 tens ... 8 - 3 ... 5 hundreds ... 5 - 1 ... 4 thousands ... 5 + 4 ... 9

Physics
or high...

Physics 11
looks good

Physics
h = -1/2 g t^2 - 10.0 t + 5.00 find the time (T) when h equals zero (impact) v = 10.0 + g T

Math
let X equal the length along the river so 50-X is the distance away from the river A = 50 X - X^2

math algebra
looks like x times 11 equals y y = 11 x + 0

maths
if the sum of the 6 scores is greater than 480, then the average is greater than 80 (87 + 75 + 79 + 68 + 84 + x) > 6 * 80 393 + x > 480

algebra
it's fairly obvious ... troubleshoot it ...

algebra
B. calculation error C. zero is correct ... the rocket has to come back down at some point

MATH
so adults were 1/3 and young people were 2/3 (9 * 350) + [7 (700 - c)] + 5 c = 7650

algebra
the problem gives the speeds in both parts ... 62 mph in the 2nd part ... and 25 mph less in the 1st part let t be the time of reduced speed ... 37 t + 62(9 - t) = 450 find the time, then multiply by speed to find the distance

Algebra 2
f(x) = cos(x/4) + 1

Math
4 d 7 f 2 sides 4! * 7! * 2

Physics 11
f = m a ... 20 + x = 4 * 3 ... x = -8 friction = m g ? ... 8 = 4 * g * ?

Math
7x + 84 = - x^2 + 40 x - 6 x^2 - 33 x + 90 = 0 (x - 30)(x - 3) = 0

algebra
in 15 min the small hose fills 1/4 of the pool, while the big hose fills the other 3/4 3/4 in 15 min means 20 min to fill

Physics
corner to corner is one length and one breadth ... distance = 40 + 30 the diagonal is the hypotenuse of a 3-4-5 triangle ... displacement = ?(30^2 + 40^2)

Lisa
the 330 and 320 form a right triangle the hypotenuse is the horizontal displacement the horizontal and vertical displacements also form a right triangle since the three directions are orthogonal ... 330^2 + 320^2 + 10^2 = d^2

Math
4 m = 24 5 m = 40 N = 40 - 24

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