Monday

January 16, 2017
Total # Posts: 1,604

**Physics**

(a) looks good part (b) may be a "trick" question velocity is a vector quantity, while speed is a scalar the answer might be zero

*January 15, 2017*

**Chemistry**

sounds like hydrogen peroxide

*January 15, 2017*

**Math**

your work looks okay C1 is 60 times C2 ... so V1 should be 1/60 of V2

*January 15, 2017*

**Chemistry - Enthalpy**

the tea (water) loses the energy gained by the spoon 250.0 * (90.00 - 85.00) * 4.184 4 sig fig ... not 5 as in your answer

*January 14, 2017*

**Physics**

1/2 * 68.6 * (4.92^2 - 1.12^2)

*January 14, 2017*

**maths**

the whole circle is 2? ... or 20?/10 3?/10 - 20?/10 = ?

*January 13, 2017*

**math**

2L + 2W = 52 L = W + 4 substituting ... 2(W + 4) + 2W = 52 4W + 8 = 52

*January 13, 2017*

**algebra 2**

7C3 * 5C3

*January 12, 2017*

**algebra 2**

16000 is 4000 above the average 4000/3200 = 1.2 sd use a z-score table to find the probability

*January 12, 2017*

**Science**

an oxide ion will take on two electrons calcium has two valence electrons potassium has one valence electron

*January 12, 2017*

**Grade 6, percentage**

70% of (840 minus boys) ... equals ... 60% of 840 588 - .7b = 504 84 = .7b

*January 12, 2017*

**algebra**

s + p = 330/11 = 30 s - p = 330/15 = 22 adding eqns ... 2s = 52

*January 12, 2017*

**Math**

correction ... 5/2 m = 2.25

*January 12, 2017*

**Math**

3b + 2m = 7 2b + 5m = 6.50 solve the system by substitution or elimination 2nd eqn times 3/2...3b + 15/2 m = 9.75 subtracting (to eliminate b) ... 5/2 m = 3.25

*January 12, 2017*

**PLEASE HELP BEEN STUCK ALL DAY CALCULUS**

nominal ... ? * 4^2 * 12 max ... ? * 4.2^2 * 12 min ... ? * 3.8^2 * 12 units are in^3

*January 11, 2017*

**physics**

a = f / m = (16890 - 1010) / 1450

*January 11, 2017*

**Algebra 2**

the factor is ... [1 + (% change)]^(years) 1 + .70 1 - .75

*January 11, 2017*

**Algebra**

the variable is to the 1st power so, yes

*January 11, 2017*

**algebra**

.....4b^2 + 2b + 1 ....._____________________ 2b-1 [8b^3 + 0b^2 + 0b - 6 ......8b^3 - 4b^2 .............4b^2 + 0b .............4b^2 - 2b ....................2b - 6 ....................2b - 1 .........................5 remainder

*January 11, 2017*

**Science**

maybe look at B?

*January 9, 2017*

**Trig**

cos = ?(1 - sin^2) 0 + ?/2 < x + y < ?/2 + ? ... ?/2 < x + y < 3?/2 the sign of the solution will be neg

*January 4, 2017*

**Algebra 2**

each year, the number of trucks is 110% of the previous year T(r) = 100 * (1 + .10)^r

*January 4, 2017*

**Science**

distance = 1/2 a t^2 871 = 25 a gravitational force must be overcome f - g = m a = 5 a f = 5 a + g

*January 4, 2017*

**Physics**

d = 1/2 a t^2 10.0 * 2 = a * 2.65^2 calculate the gravitational acceleration (a) ... f = m a ... f / m = a f = M * m * G / r^2 ... f / m = M * G / r^2 ... a = M * G / r^2 M is the planet's mass G is the universal gravitation constant r is the planets radius (in meters)

*January 3, 2017*

**Physics**

100 kg/s energy (work) = m * g * h ... = 100 kg * 9.8 m/s^2 * 100 m ... = Joules energy / time = power ... Joule / s = watt

*January 2, 2017*

**Spanish**

hola ipap da loemlo

*December 18, 2016*

**Math Homework**

looks good

*December 17, 2016*

**Math**

.03 j = .05 s j = s + 500

*December 9, 2016*

**Math**

Will you marr... me

*December 9, 2016*

**Math**

x + y = 24 y + 12 = z x + y + 12 = 36 x + z = 36 (x + z) / 2 = 18

*December 9, 2016*

**Physics**

w = f * d Newtons * Meters = Joules

*December 8, 2016*

**Algebra**

18 - 7 17 - 8 16 - 9 15 - 1 14 - 2 13 - 3 12 - 4 11 - 5 10 - 6

*December 8, 2016*

**Physics**

radius is half the diameter

*December 8, 2016*

**Algebra**

m = (y2 - y1) / (x2 - x1) if x and y change in the SAME direction (up or down), then the slope is positive if they change in opposite directions, the slope is negative -5/-3 is not the same as -5/3 ... one is positive, the other negative

*December 8, 2016*

**math**

60 seconds in a minute

*December 8, 2016*

**physics**

w = f * d (Joules, in this case)

*December 8, 2016*

**Probability Help**

there are [(40 * 39) / 2] separate pairs of people the probability of two people not having the same birthday is (364 / 365) the probability that none of the group have the same birthday is ... (364 / 365)^(20 * 39)

*December 8, 2016*

**Algebra**

s + a = 350 1s + 3a = 450 elimination looks pretty good

*December 7, 2016*

**Physic**

constant velocity - no acceleration net force is zero friction and push cancel each other

*December 7, 2016*

**Physics**

figure???

*December 7, 2016*

**math**

point-slope Y - y1 = m (X - x1)

*December 7, 2016*

**Geom A**

6. try again the sides are in the same size order as their opposite angles <C is the largest, so AB is the largest side 7. try again any one side must be LESS THAN the sum of the other two sides

*December 7, 2016*

**Algebra**

There is no twins age given, sorry, this is the full question

*December 7, 2016*

**Algebra**

I am 6 years older than my wife. Our twins go to the local comprehensive school. One of the twins noticed that the sum of their ages divided into the product of my age and the age of my wife is 63. How old am I?

*December 7, 2016*

**math**

looks good

*December 6, 2016*

**Calculus applications**

The bending moment (M) along a beam is M = WLx/2 -Wx2/2 kNm where x is the distance of a beam length L from the left hand end. W is the weight per unit length. (a) Shear force is calculated as the differential of bending moment. Find an expression for shear force and determine...

*December 5, 2016*

**Math**

how can the perimeter be less than the diagonal? you found one of the sides...the perimeter is all four

*December 4, 2016*

**Algebra**

d + n = 28 10d + 5n = 195 solve the system ... substitution or elimination

*December 4, 2016*

**math algebra**

you have everything you need just crank the crank

*December 4, 2016*

**math**

2 = [1 + (p / 100)]^2 ?2 = 1 + (p / 100)

*December 4, 2016*

**Maths**

try nesting polygons ... going from the outside in connecting adjacent points gives 64 sides (chords) every other point gives 32 sides every 3rd point. etc...

*December 3, 2016*

**Physics**

a) looks good b) you know the kinetic energy at the top ... just add the gravitaional potential (mgh) across the loop to find the bottom speed

*December 3, 2016*

**Math**

14 * 13 * 12 * 11 * 10 * 9 * 8 * 7 * 6 1st student has choice of 14 chairs ...2nd student, 13 chairs ... yada, yada

*December 2, 2016*

**Maths**

the horizontal component of P (along the rod) is [P * cos(30º)] the vertical component is [P * sin(30º)] the normal reaction is the block's weight (m * g), minus the vertical component of P you surmise correctly re: the result of P exceeding 392 Newtons

*December 2, 2016*

**Interest**

4000 * [1 + (.05 / 12)]^(5 * 12)

*December 1, 2016*

**physics**

1/2 * m * v^2 = 1/2 * .058 * 58 answer is in Joules

*December 1, 2016*

**physics**

a = f / m kg and N means m/s^2

*December 1, 2016*

**Physics**

? may be 3º ... the wording is ???

*November 30, 2016*

**Algebra 2**

good chioce

*November 30, 2016*

**math**

the 54th term is 50 differences from the 4th term

*November 30, 2016*

**Math**

m + n = 3 ... n = 3 - m m * n^2 = m * (3 - m)^2 ... = m^3 - 6 m^2 + 9 m the max appears to be infinite

*November 30, 2016*

**Science**

yes, gravity counts 22 / (10 * g)

*November 30, 2016*

**Algebra 1 B**

2 is good 3 needs work

*November 30, 2016*

**physics**

not sure about impossible... this is around escape velocity

*November 29, 2016*

**physics**

centripetal acc = v^2 / r ... v is the tangential velocity 16.7 = v^2 / 6.41E6 v / r = angular velocity (in radians)

*November 29, 2016*

**algebra**

n = 1000 * e^(.11 * 2)

*November 29, 2016*

**Calculus**

s(t) = -16t^2 + 1600 t the time of max height is on the axis on symmetry ... t = -1600 / (2 * -16) the slope of the tangent (1st deriv) is equal to zero at max height

*November 29, 2016*

**geometry**

looks like the line segment was doubled scale factor is two

*November 29, 2016*

**science**

molar mass of Bi is 208.98 g ... so there are 2 moles of Bi 6 moles of F will react to form BiF? the molar mass of F is 19.0 g add the mass of the Bi and the mass of the F to find the grams of BiF?

*November 29, 2016*

**Chemistry**

conservation of mass

*November 29, 2016*

**Math**

15.85 + .75 = 3n + 2(3.95) + 1.23

*November 29, 2016*

**Math**

1. n 2. 2n 3. 2n + 5 4. 100n + 250 ... moves chocolate times into hundreds place 5. 100n + [2016 or 2015] ... sets up #6 to yield age 6. 100n + age [(50[2(n)+5])+176?]-birth year

*November 29, 2016*

**algebra**

thanks for the catch, Reiny too late to be working on this stuff

*November 27, 2016*

**algebra**

(90 / c) + [130 / (c + 20)] = 4 90 c + 180 + 130 c = 4 c^2 + 80 c c^2 - 35 c - 45 = 0 use quadratic formula to find c

*November 27, 2016*

**6 grade math area perimeter**

area looks good perimeter might be 16 ... check it

*November 27, 2016*

**6 grade math area perimeter**

looks good

*November 27, 2016*

**Physics**

it accelerates for 4 s ... up to 8 rad/s then spins for 11 s ... 88 rad the ave vel during acceleration is ... ) + 8) / 2 = 4 rad/s ... spins 16 rad 104 rad total ... divide by 2? to find revolutions

*November 27, 2016*

**calculus**

the friend's distance north is 30 t your distance east is ... 40 - 20 t it's a right triangle use Pythagoras to find the hypotenuse ... which is the distance find the minimum - with respect to t

*November 26, 2016*

**Physics**

the centripetal force (m v^2 / r) is equal to the gravitational force ... G M m / r^2 v^2 = G M / r ... = 6.67E-11 * 5.98E24 / 7.12E6 the period is the speed divided into the orbital circumference

*November 26, 2016*

**Physics , static fluids**

the ice is 92% as dense as the water so 92% of the block is submerged when it floats that leaves 8% exposed

*November 26, 2016*

**Algebra**

s + L = 40 s + 6 = L subtracting the equations ... eliminating s L - 6 = 40 - L

*November 26, 2016*

**Physics**

the supports each exert 98 N to support the plank one support exerts [490 N * m / 3] to support the person the other support exerts ... 490 N - [490 N * m / 3]

*November 26, 2016*

**Physics , static fluids**

the buoyancy force is the difference in the air weight and immersed weight

*November 26, 2016*

**Physics , static fluids**

hello (again) 8.6 meters is 860 cm if you picture a stack of 860 cm cubes of water, what is the force at the bottom? ... 860 gm * g ... this is the force on one cm^2 .86 kg * 9.8 m/s^2 = f a Pascal is one Newton per m^2 ... a kPa is .001 N per cm^2

*November 26, 2016*

**Physics**

you can use the density of water and the depth to find the pressure the "rule of thumb" for diving is one atmosphere for every ten meters of depth

*November 26, 2016*

**Physics**

e = 1/2 k x^2 ... (kind of like KE) 2.0 = 1/2 * 100 * x^2

*November 25, 2016*

**Physics**

look up Doppler shift formula

*November 25, 2016*

**Maths**

2 = (1 + .06)^t log(2) = t log(1.06) t = [log(2)] / [log(1.06)]

*November 23, 2016*

**Algebra 2 (Please help Ms. Sue!)**

use synthetic division

*November 23, 2016*

**Algebra**

(d / 55) + (d / 35) = 50 - 10

*November 22, 2016*

**Physics**

momentum is conserved find the momenta in x and y for the two decay products the two y momenta add to zero, and the two x momenta equal the original add the vectors to find the 234Th velocity

*November 22, 2016*

**pre calc**

100% - 30% = (1/2)^(2 / h) log(.7) = (2 / h) log(1/2) h = 2 log(1/2) / log(.7) (after a week) = (1/2)^(7 / h)

*November 22, 2016*

**Algebra**

it stops at the top, so the average velocity is ... (103 + 0) / 2 gravitational acceleration is 32 ft/s^2 , downward so the time to reach the peak is ... 103 ft/s / 32 ft/s^2 r * t = d

*November 22, 2016*

**Physics**

momentum is conserved, so the truck's loss is the car's gain 7500 kg-m/s / 750 kg = ?

*November 22, 2016*

**physics**

radio waves travel at the speed of light (c) ... 3E8 m/s the distance from Venus to Earth depends on where each planet is in its orbit around the Sun

*November 22, 2016*

**technical drawing**

85 m is 85000 mm 85000 mm / 10000 = ?

*November 22, 2016*

**science**

x + y = 10 3.1 x + 2.5 y = 25 solves easily by inspection (observation)

*November 21, 2016*

**physics**

6000 Nm/s = 6 kw

*November 21, 2016*

**Physics**

the object displaces 1/5 of its weight in water, so it is 5 times the density of water the weight change in the other liquid is 2/3 of the change in water, so the other liquid is 2/3 the density of water

*November 21, 2016*

**Chemistry**

the Ar will effectively be "squeezed" into 80% of its previous volume this will increase the tank pressure to 125% of the original the pp of Ar is 80% of the total the pp of nitrogen is 20%

*November 20, 2016*