# Posts by Scott

Total # Posts: 2,321

Algebra
yes

physics
drop speed relative to rest ... s = 90 kph / tan(40º) drop speed relative to vehicle ... s = 90 kph / sin(40º)

Math
6C3 combination implies that order is not a factor

math
Q IV ... x is positive, y is negative (b,-a)

physics
work = m g h in real life, terminal velocity becomes a factor

physics
60 mph = 88 ft/s a) the average speed while stopping is 30 mph or 44 ft/s ... the stopping time is ... 200 ft / 44 ft/s divide the initial speed by the stopping time to find the acceleration b) same process as a) but with a different initial speed

Math
D = s + 1 s = b + 3 ... b = s - 3 D + s + b = 31 s + 1 + s + s - 3 = 31 find s, then substitute back

Math
the area is found by multiplying the base by the height

Physics
is the lift moving up or down it makes a difference

maths
sin(?) = 18 / 30

Algebra 2
[(a1 + a23)/2] * 23 = s23 [(10 + a23) / 2] * 23 = 2760

Math
c) the pedal is at 32 cm twice per revolution ... going down and going up 4th time would be 2nd time during 2nd cycle

physics
the change in momentum of the car is equal to the change in momentum of the truck

Math, identities and equalities
expand the cube of the binomial ... the x^3 terms will cancel ... consolidate like terms match the term coefficients with the left hand side solve the resulting equations for a, b, and c

Physics 11
the work calculation is the total work the components are not separable ... not enough information

Mathse
use vector addition on the two components ... a^2 + b^2 = c^2

Physics 11
the friction/work hint is a good one 90 * g * .6 * d = 720

OH for three... no such thing as an equilateral right triangle only one way each to make the other two

Physics
energy = work 2200 J = 1100 N * ? m

Math
looks good

Math
x^3 + 3x^2 + 2x = x^3 + 21 3x^2 + 2x - 21 = 0 (3x - 7)(x + 3) = 0 x + 3 = 0

logs
yes ... that would equal t

physics
the horizontal distance to the edge of the water is ... 10.0 m * tan(40º) the time to fall the 10 m is ... ?(2 * 10 / g) divide distance by time to find the speed

squaring a binomial ... use FOIL (2?5)^2 + 2 * 2?5 * 3?7 + (3?7)^2 20 + 12?35 + 63 = 83 + 12?35

Math
the 3rd side of a triangle must be long enough to connect the ends of the other two sides ... it must also be short enough that the other two sides can connect its ends difference of other two sides < ... 3rd side < sum of other two sides

Physics
a) 20 rad/s * 40 cm/rad b) [a)] * 6 s / 100 cm/m

Physics

Science
ave vel = 10.0 m / 5.0 s = 2.0 m/s final is zero, so initial is ... 4.0 m/s deceleration is ... 4.0 m/s / 5.0 s = 0.80 m / s^2

Math
the exponents form a converging geometric series multiplying (product) numbers with the same base (3 in this case) means adding the exponents 3^(1/3 + 1/9 + 1/27 + ...) there is a formula for the sum of an infinite geometric series ... look it up

algebra
subtracting 4 ... x^2 - x - 6 = 0 factoring ... (x + 2)(x - 3) = 0 individually ... set each factor equal to zero ... solve for x

Algebra
n is the number of the term plug in 1, 2, 3, and 4 for n to find the 1st four terms

Math
5x + 4y = 210 ... 4y = 210 - 5x A = 4 x y = x (210 - 5x) = 210x - 5x^2 max A on axis of symmetry ... x = -210 / (2 * -5) = 21

geometry
(a) if the smaller circle is inside the larger circle , the center-to-center distance is ... 7 cm (b) if the smaller circle is outside the larger circle , the center-to-center distance is ... 19 cm

Science
gps operates by using satellite signals

Physics
a. the acceleration is a function of gravity...it is essentially constant b. see a. gravitational acceleration (g) is 9.8 m/s^2 ... for every second you fall, you go 9.8 m/s faster for c. and d. , multiply the free-fall time by the acceleration (g)

math
9 * 5 = 45 man-days ... like man-hours, only longer 45 man-days / 6 men = ?

physics
V1 = speed at top of window V2 = speed at bottom of window h = height of window T = time of passage [(V1 + V2) / 2] * T = h V2 = V1 + g T [(V1 + V1 + g T) / 2] * T = h V1 T + (g T^2 / 2) = h V1 = (h / T) - (g T / 2)

Algebra2
the common difference is 6 -2 + (49 * 6) your answer looks good

math homework
the speed of the boats is not mentioned...it is a factor

math
h = -1/2 g t^2 + 40 t + .25 h = 0 , g = 9.8 m/s^2 solve for t ... quadratic formula works good ... you want the larger positive value

College Physics
m * g * .15 * 30 = 20000

Physics
forgot a small detail ... v0 is squared ... v0^2

Physics
R = horizontal range (m) v0 = initial velocity (m/s) g = acceleration due to gravity (9.80 m/s2) ? = angle of the initial velocity from the horizontal plane (radians or degrees) R = v0 * sin(2?) / g

Math
six 5's wide , and four 5's long 6 * 4 = ?

math
all the outcomes have an equal chance why wouldn't they?

College Algebra
120 = -16 t^2 + 96 t + 12 0 = -4 t^2 + 24 t - 27 use quadratic formula to find t

algebra plz help!!
(t^2 - 8q)(t^2 + 3q)

Math
vertical cross-sections are triangles horizontal cross-sections are squares

7ee
100% + 20% = 1.2 7.65 * 1.2 * 40 = ?

Science
although it may actually require more work (due to friction), the ramp reduces the necessary force and usually the power needed

Science
work = energy a) 182 * .380 = 1/2 * .0220 * v^2 b) .770 * 182 * .380 = 1/2 * .0220 * v^2

Functions
[1 + (2 * .137)] * (p - 10000) = 7500

Science
looks good

science
2 half-lives ... 80 * 1/2 * 1/2

Math
the common difference is 7 7 n - 19

Algebra 2
check the definition of a radian

algebra 1
the dimensions are factors of the expression ... you multiply them together to get the area the factors are ... (x - 7) & (x + 2)

csc = 1 / sin = r / x sin (and csc) are negative in quads III and IV

Science

physics
the Mach number is how many times the speed of sound an object is moving find the speed of sound based on the air temperature

Physics
what about the time it takes for the clam to fall 40 m?

Maths plez help ASAP

Algebra 2
2? rad = 360º ... ? rad = 180º 3 * 180 / 5 = ?

Math (Calculus II) (Weird Work Problem Setup Help)
the width equation is due to the taper of the tank as y goes from 0 to 3, the width goes from 2 to 1 the volume of the fuel increment is ... l * w * dy ... the force increment is the volume times the fuel density

maths
20 / d = tan(30º)

math
25/30 - 18/30 = 7/30 7/30 v = 21 L

Mathematics
tan(?) = 5/8

Math
1. xy = 15 2. substituting ... -3x + 5 = x^2 + 2x - 45 ... 0 = x^2 + 5x - 50 ... factoring ... 0 = (x + 10)(x - 5) ... x = -10 , x = 5 substitute the x-values back to find the corresponding y-values 3. -?(18/12) = ±?(3/2)

science
a) KE = 1/2 * m * v^2 (Joules) ... minus zero from start b) see a) ... work & energy the same c) d = 1/2 * a * t^2 (meters) d) f = m * a (Newtons)

Geometry
2 * ? * 7 * (80/360)

math
2 hr = 120 min ... 20 six min intervals ... 20 units per machine the numbers don't seem to match up...

stats
2 sd below the mean and 1 sd above 47.7% below , and 34.1% above

Trigonometry
Pythagoras ... x^2 + 35^2 = 37^2

Trigonometry
the diagonals bisect each other use the law of cosines to find the sides

science
the molar mass of HCl is ... 36.46 g

Mathematics
pyramid ... v = 1/3 (base area)(height) ... v = 1/3 * (2s)^2 * s = 4/3 s^3 prism ... v = l w h = 2s * 2s * s = 4 s^3

chemistry
the speed of sound in air is temperature dependent 337.5 m/s 10ºC

physics
the "beats" are the frequency differences a) 440 Hz ± (12/2) Hz b) 435 Hz ± (33/3) Hz which frequency is in both possibilities?

Math
6 min is correct ... but it is after 5:00 - not before

Math (Algebra)
if you subtract the equations (to eliminate y), you still end up with ... 0 = x^2 - x - 2 ... but you have used elimination even with elimination, you have to substitute back at some point to find all the variables

Math (Algebra)
x^2 = x + 2 x^2 - x - 2 = 0 (x - 2)(x + 1) = 0 x - 2 = 0 ... x = 2 x + 1 = 0 ... x = -1 the line intersects the parabola in two places plug the x-values into the equations to find the corresponding y-values

physics
time up equals time down ... Tu = Td half of the flight time (Tu) is spent climbing to the max ... h = 1/2 g (Tu)^2 the vertical velocity equals ... g Tu initial velocity is the vector sum of the vertical and horizontal ... V^2 = (Vh)^2 + (Vv)^2

Physics
Ff = ? m g cos(30º)

Honors Algebra
450 = 100 e^(kt) 4.5 = e^(6k) ln(4.5) = 6 k k = [ln(4.5)] / 6

physics
use the average speed on an interval, multiplied by the time of the interval add the three intervals

Physics
the two players experience equal but opposite impulses from the collision M1 * A1 = M2 * A2

MATH
half of the letters are vowels so, one half times one half

Math Check! #3
8C4 = 70

Math Check!
yes

physics
looks good

Physics
the force component of the box's weight along the ramp is ... m g sin(30º) the frictional force is ... ? m g cos(30º)

math
1st ... 1/4 * 7/16 2nd ... 1/4 * 7/15

Math
it's binary ... correct or incorrect P(correct) = 1/4 ... P(incorrect) = 3/4 (c + i)^50 .25^50 + 50 .25^49 .75^1 + 1225 .25^48 .75^2 ... + 1225 .25^2 .75^48 + 50 .25 .75^49 + .75^50 this is the expected outcomes for a simulation you could roll a 4-sided die (tetrahedron) ...

Statistic
I would agree

physics
30 km/s in a car!?!? that's about 3 times escape velocity

Math
10 - .13 < w < 10 + .13

Physics
a mole of gas occupies 22.4 L at 0ºC and 1 atm moles = (4.5/22.4)(273/350)(22/101) molecules = moles * Avogadro's number

Algebra
3 (b - c) = b + c 3b - 3c = b + c ... 2b = 4c

Geometry
the slant part of the cone (lateral area) is a sector of a circle the radius of the circle is the slant height of the cone ... Hs^2 = 62^2 + 12^2 the partial-circumference of the sector is the circumference of the base of the cone ... 24 ? LA = ? * Hs * 12 = 2381 base area...

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