# Posts by Scott

Total # Posts: 2,320

**Math**

the outside diameter is 8 ft more than the inside ? times 8 ft is about 25 ft 802 is WAY high

**precal**

it takes a second for the coin to reach max height, 16 ft above the balcony d = 1/2 a t^2 346 - 90 = 1/2 g t^2 solve for t, add in the 1st second

**Math**

50 cm * ? * 25

**Physics**

the deceleration is ... (13.0 -10.9) m/s / 2.20 s ... slightly less than 1 m/s^2 so it takes about 13 s to stop ... during which the average speed is ... (13.0 + 0) m/s / 2

**Science**

f = m a ... w = m g ... m = w / g

**Physics**

1/2 m v^2 = m g h h = v^2 / (2 g)

**algebra**

the question asks about "carriers" (like the RL parent) what percent is like the RL parent?

**math**

2 equations and 2 unknowns, just solve the system by substitution or elimination

**math**

looks good

**algebra**

the distance is the hypotenuse of the right triangle ... use Pythagoras

**Algebra**

the max A lies on the axis of symmetry Wmax = -b / 2a = -200 / (2 * -2) = 50

**calculus**

the quadratic solutions are relative max/min points on the graph (you obviously want the max) test the solutions in the original equation x < 4 because of the 8 in side

**maths**

the reflection is along a line through the center of the circle, perpendicular to the given line slope of perpendicular is ... -1 equation of perpendicular ... y-3 = -1 (x-2) ... y = -x + 5 intersection with reflecting line ... (1,4) center of reflected circle ... (0,5) center...

**Math**

subtract 8 ... -m/5 > 2 multiply 5 ... -m > 10 divide -1 ... m < -10

**Gr 12 Data**

a) 2^5 c) 2^3 ... arrangements of 3 middle coins d) 2^2 ... arrangements of 2 end coins e) yes , a coin toss is a coin toss

**science**

the masses are inversely proportional to the heights ... higher height means lower mass Hb Mb = Hj Mj

**geometry**

the general equation is ... (x - h)^2 + (y - k)^2 = r^2 r is the radius , (h,k) is the center

**Statistics**

25 people bought 35 cones so 10 people bought both 5 only van - 10 both - 10 only choc

**geometry**

(x - h)^2 + (y - k)^2 = r^2 the equation defines a circle of radius, r; centered at (h,k)

**math**

? rs = 20 b ... 1.1 ? rs = 22 b ? rs = 22 (b - .25) + .20 = 22 b - 5.3 .1 ? rs = 5.3 ? = 53

**Maths**

adding 5 ... | x | > 11 x < -11 , x > 11

**Math**

looks like #5

**Math**

how many are what age?

**math**

it's a 5-12-13 Pythagorean triple

**Math**

remember the hierarchy of operations ... PEMDAS adding 5 ... c/4 = 9 multiplying by 4 ... c = 36

**word problem**

Ar + Au + D + B = 267 Ar = Au - 8 D = 2 Au B = 5 Au + 5 substitute in the 1st equation to find Au ... then substitute back to find the others

**Math**

looks good

**Physics 20**

p1 exerts the same force on p2 that p2 exerts on p1 f = m a ... m1 a1 = m2 a2

**Science**

rethink #2

**algebra**

subtracting 5 shifts the 1st function 5 units down to give the 2nd function

**binomial distribution**

(s + f)^5 s^5 + 5 s^4 f + 10 s^3 f^2 + ... 10 s^2 f^3 + 5 s f^4 + f^5 s = p(success) = .687 f = p(failure) = 1 - p(success) = .313

**Math**

the terms are getting larger ... diverging

**graphing help?**

there is a website called fooplot you should use it

**Bio chem**

How many mL of 0.80 molar NaOH must be added to 20 ml of 0.40 of molar propionic acid, in order to produce a solution with a pH of 4.89? (PKa of propionic acid is 4.89.)

**consumer math**

2000 (1 + .08)^6

**math**

85000 + [(39637 - 35416) / .45]

**Physics**

boat components ... W ... 25 cos(35º) = 20 ... N ... 25 sin(35º) = 14 add the boat components to the current (14 N + 18 S) + 20 W = 20 ... the tan of the angle is ... S/W ... arctan(4/20) = 11º ... [W11ºS]

**Math**

the trip times are not the same, so the average speed is not 9 mph sorry, Ms. Sue

**Math**

d = r t ... t = d / r 27/60 = (d / 10) + (d / 8) 54/120 = (12 d / 120) + (15 d / 120) d is the distance to the lake

**Math**

get all the equations into slope-intercept form (y = mx + b) 1. the slopes are the same but the intercepts are different ... the lines are parallel ... they never intersect so no solution 2. the slopes are the same and so are the intercepts ... the lines lie on top of each ...

**Math, Algebra**

(2s + 5)(s - 6) = s^2 2s^2 - 7s - 30 = s^2 s^2 - 7s - 30 = 0 (s - 10)(s + 3) = 0

**trig**

Upper? plane ... N component ... 450 kph cos(45º) ... E component ... 450 kph sin(45º) wind ... N component ... 60 kph cos(30º) ... W component ... 60 kph sin(30º) add the components to find the resultant vector

**math**

it's four times as tall in the picture, so it's four times as tall in real life

**Math**

p + g = 20 4p + 2g = 70 solve the system using substitution or elimination

**7th grade math**

10 ft long and 4 ft wide is 40 ft^2

**Algebra**

4 w + 2 k = 62 w + k = 21 solve using substitution ... or elimination

**physics**

centripetal force is ... m v^2 / r a) (2 ? r) / 6.10 m/s b) m [g - (v^2 / r)] c) m [g + (v^2 / r)]

**Physics (I have a test tomorrow)**

the average speed of the car is 50 kph convert the speeds to m/s find the time to cover the 85 m find the change in kinetic energy ... KE = 1/2 m v^2 the work against resistance (friction) ... work = f d = 750 N * 85 m work and energy are the same thing add the work and the ...

**Physics**

the forces in c and d are normal (perpendicular) to the direction of motion of the car they do no work

**physics problem**

(2 * ? * 34 cm) / 39 m/s watch your units

**Science**

correct why the confusion?

**Science**

sounds like fermentation if there is oxygen, you get vinegar instead of wine

**math**

a- A = 12000 [1 + (.039/12)]^(6 * 12) b- subtract 12000 from a-

**maths**

no the ratio between the sides is not equal

**math**

A does 4/60 and B undoes 3/60 so 1/60 completed every 2 days after 112 days, 56/60 are done ... A completes the work on the 113th

**algebra**

6C3 ... 6! / (3! * 3!)

**Math**

it's a system of equations 5 V + 3 C + 2 M = 675 V = 2 C M = C + 75 substitute and solve

**Math**

x = 6 * 2^n

**physics**

cool the steam to 100ºC condense the steam cool the water to 0ºC freeze the water two specific heats heat of vaporization, and heat of fusion

**Math**

(300 / 500) * 250,000

**Physics 1401**

the center of mass of the stick is at the 50 cm mark ... 10 cm from the balance point the 6 g is 30 cm from the balance 10 * m = 30 * 6

**Physic sucks 1401**

the masses are linked by the string and have the same acceleration ... one upward and the other downward f = m a ... a = f / m (t - m1 g) / m1 = (m2 g - t) / m2 2t - 2g = 2g - t ... 3t = 4g ... t = 4/3 g the largest mass is 2 kg ... it gives about 20 N of force with the system...

**Geometry Proofs**

My teacher said she gave us everything.

**Geometry Proofs**

Trying to solve a proof. Triangle ABC. D is a point on side AC and E is a point on side BC. There is a line from Angle B to Point D and a line from Angle A to Point E. My Givens are AD = BE and BE>AE. I need to prove BC>AC. This is for my 7th grade geometry class. Thank ...

**Chemistry**

no some are not water soluble

**math**

look at 100,000 people 800 have it ... 56 will show negative ... 744 will show positive 99200 don't have it ... 2976 will show positive probability of accurate positive ... 744 / (744 + 2976)

**math**

(2 * 27.5) + 30/2

**Math - combinatorics/ permutations**

looks good

**Chemistry**

molarity is moles solute per liter of solution 0.05144 moles / .38 L = ? significant figures?

**science**

a + b = 29 a - b = 5 2a = 34 ... a = 17 ... b = 12 (17 + 3)^2 + (12 + 3)^2 = r^2

**Physics**

m g h + 1/2 m v^2 = 1/2 m V^2 (2 * 9.8 * 65) + 12^2 = V^2

**Mathematics.**

ER , 1/5 off , 4/5 normal , 80% normal ... normal = 64 / .80 MW , 15% off , 85% normal normal = 64.60 / .85

**Math**

the sides and angles must be congruent if they are "regular" octagons, the side lengths must be equal

**math**

looks good

**physics**

m g h / t ... 75 * 10 * 12 * .20 / 5

**Physics**

on the side of the -9 away from the +16 let d = distance from -9 16 (d + 8)^2 = 9 d^2

**Math**

the nearest point, the end of the chord, and the end of a diameter (opposite the point) form a right triangle the half of the chord forms the altitude of the triangle 4 / 7 = 7 / (d - 4) solve for the diameter (which is twice the radius)

**Science**

the product of force and time is 3 3 N for 1 s isn't realistic for golf, but it's easy to work with f = m a ... 3 = .05 a ... a = 60 m/s^2 t = 1 s , so the velocity is 60 m/s

**Precalculus -- Systems of Equations**

thank you, bob we all try to bring enlightenment where we can

**Precalculus -- Systems of Equations**

x^2 + y^2 = r^2 is a circle of radius r, centered at the origin x - 2y = 8 is a line the question is asking what r must be for the line to be tangent to the circle the radius is perpendicular to the line at the point of tangency ... it is the shortest distance from the line to...

**Geometry**

the radius of the tank is 36" (3 ft) looking a the tank in cross section the width of the gasoline surface is the base of an isosceles triangle the height is ... 36 - 18 the sides are ... 36 use the vertex angle to find the area of the sector of the circle then find the ...

**math**

6/7 = 0.857142857142... 6 digits repeating 327/6 = 54 R3 ... 3rd digit of 6

**Math**

A = 1/2 * b * h

**Math**

3 congruent triangles make up the 3 sides the area of a side is ... 198 / 3 cm^2 the slant height is the height of a triangular side you have the area and the height of a triangle ... how do you find the base length?

**Math (Physics)**

did you google Hubble's Law?

**Solid figures**

? * (d/2)^2 * 42 = 30 * 231

**6th Grade Math (Please Help It's Getting Late)**

sale price = list price - discount

**science**

refraction is the quality that causes the bending (focusing) of light rays it's what allows lenses to function

**Science**

sure ... post them and someone will check

**Science**

looks good

**Science**

a mole of O2 gives 2 moles of ZnO the molar mass of O2 is ... ? 2.25 g is ? moles of O2 the molar mass of ZnO is ... ?

**Maths**

741 / (9 + 105) = 6.5 ... so there are 13 terms (105 - 9) / (13 - 1) = 8 ... the common difference is 8

**Physics**

f = m v^2 / r f = 43 N * (59/15.89)^2 / (.948/2.1)

**math**

check the sign

**math**

tan(?) = 8/10

**physics**

2) 2 sec up and 2 sec down 1) ave vel = 10 m/s 10 m/s * 2 s = ?

**Math (Physics)**

the answer is asking for nanometers units?

**Math (Physics)**

Rn = n^2 * R1 2.50E-3 m = n^2 * .53E-10 m En = (13.6 / n^2) eV

**No one is helping me :/ ??**

3 as an asymptote means that is the value that the function approaches as x goes to infinity

**college algebra**

only if the system is dependent ... which it isn't