# 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

**Someone please help!!! Math**

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

**Algebra 1 Please Help**

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**

a) 6 * 2 ? / 4 = ? rad/s b) ? rad/s * 15 cm/rad

**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

**4th grade math - line plot**

yes

**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)

**grade 11 math**

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

**Science**

1/4 of the load

**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**

your answer is for none of the coins landing on heads 8 out of ten tosses had at least one head

**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...