# Posts by Scott

Total # Posts: 2,121

**physics**

friction force = centripetal force ? m g = m v^2 / r ? = v^2 / (g r)

**Physics**

the dimensions are given to 3 sig fig ... that's what the answer should have 1 m^3 = (3.28 ft)^3 v = 43 * 18 * 15 * 3.28^3 ft^3 ... use 3 significant figures in the answer

**serial dilutions**

the mix is 1.5 diluent to .5 solution each dilution results in a solution that is 1/4 the concentration of the added solution ... .5 mL / (.5 mL + 1.5 mL)

**Algebra 2**

?n = n^(1/2) ?(8 x^3 y^5)

**Algebra 2**

(7x-2)^1/4 = 5 7x - 2 = 625

**Math**

horizontal (x) component ... magnitude * cosine vertical (y) component ... magnitude * sine

**Algebra**

try this (.08 * x) + [.07 * (x - 1400)] = 217

**Physics**

h = 1/2 g t^2 ... ?(2h/g) = t the time is directly related to the square root of the height

**Physics**

cable exerts an upward force gravity exerts a downward force find the net force a = f / m

**Math**

the difference is -7 the 5th term is 10 differences before the 15th term

**physics**

average velocity during penetration is ... (500 + 0) / 2 time = distance / velocity

**science**

impulse is the change in momentum over time

**physics**

the force of the Earth on the ball is the same as the ball on the Earth f = m a use the drop time to find the velocity v = a t

**Math**

horizontal means zero slope set f' equal to zero and solve for x

**College Math - Quantitative Reasoning**

.93^3 = .804357 1 - .804357 = .195643 rounds to 19.6%

**College Math - Quantitative Reasoning**

what do you think is the right answer? the problem statement is not correct your calculations are fine

**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

**Chemistry**

sounds like hydrogen peroxide

**Math**

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

**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

**Physics**

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

**maths**

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

**math**

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

**algebra 2**

7C3 * 5C3

**algebra 2**

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

**Science**

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

**Grade 6, percentage**

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

**algebra**

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

**Math**

correction ... 5/2 m = 2.25

**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

**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

**physics**

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

**Algebra 2**

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

**Algebra**

the variable is to the 1st power so, yes

**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

**Science**

maybe look at B?

**Trig**

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

**Algebra 2**

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

**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

**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)

**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

**Spanish**

hola ipap da loemlo

**Math Homework**

looks good

**Math**

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

**Math**

Will you marr... me

**Math**

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

**Physics**

w = f * d Newtons * Meters = Joules

**Algebra**

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

**Physics**

radius is half the diameter

**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

**math**

60 seconds in a minute

**physics**

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

**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)

**Algebra**

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

**Physic**

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

**Physics**

figure???

**math**

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

**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

**Algebra**

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

**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?

**math**

looks good

**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...

**Math**

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

**Algebra**

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

**math algebra**

you have everything you need just crank the crank

**math**

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

**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...

**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

**Math**

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

**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

**Interest**

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

**physics**

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

**physics**

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

**Physics**

? may be 3º ... the wording is ???

**Algebra 2**

good chioce

**math**

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

**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

**Science**

yes, gravity counts 22 / (10 * g)

**Algebra 1 B**

2 is good 3 needs work

**physics**

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

**physics**

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

**algebra**

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

**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

**geometry**

looks like the line segment was doubled scale factor is two

**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?

**Chemistry**

conservation of mass

**Math**

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

**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

**algebra**

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

**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

**6 grade math area perimeter**

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

**6 grade math area perimeter**

looks good

**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

**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

**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

**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

**Algebra**

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

**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]

**Physics , static fluids**

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

**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