# Posts by Scott

Total # Posts: 2,150

**chem**

the partial pressure is the total pressure, multiplied by the fraction of the gas involved in this case ...ppO = .32 * 132 atm ...ppN = (1 - .32) * 132 atm

**SCIENCE**

the 2nd one

**PHYSICS**

downward velocity at impact ... v = √(2 * 10 * 20) = 20 m/s upward velocity after impact ... v = √(2 * 10 * 15) = 10√3 m/s accel = Δv / t = (20 + 10√3) / .01 ...units are m/s²

**College algebra**

100 + 5 x = 103 + 4 x

**Algebra**

2.75 < 2.25 + (750 / p) < 3.75 .50 < 750 / p < 1.50 2 > p / 750 > 2/3 1500 > p > 500 none of the responses seem to be correct

**age problems(please help)**

S = 3s ... t = 5S = 15s t + 5 = 5(s + 5) = 5s + 25 3t + 15 = 15s + 75 substituting ... 3t + 15 = t + 75 solve for t

**Physical Science**

heat the ice to 0º melt the ice heat the water to 20º look up the heat of fusion for ice and the specific heats for ice and water

**physics**

the distance is closing, so the frequency is higher F = 50kHz * [1450 / (1450 m/s - 450 km/hr)]

**Calc-Math**

you need to use the product rule for xy x dy/dt + y dx/dt

**Physics**

its average speed while stopping is 30 mi/h there are 3600 sec in an hr , and 5280 ft in a mi d = 30 * 5280 * 6 / 3600 ... feet

**Math**

10 = 1/2 * g * t^2 20 / 9.8 = t^2

**math**

The area if a rectangle is x3y4. Which expression represents the length if the width is x2y

**physics**

C = Q / 100...100 C = Q capacitors add in parallel the charge is the same (redistributed) C + 10 = 100 C / 30 solve for C

**Math**

C. The answer is C, -7.

**Math**

It is impossible. 12, 14, or 16 may work, but I think you should give up on this equation...

**Gen Chem**

Thank you DrBob222!

**Gen Chem**

Knowing the MW of salicylic acid (138.12g/mol), design a procedure to make 100mL of a 0.0050M salicylic acid solution.

**General Chemistry**

That's why I was confused, it just states that the Fe(OH)3 has a solubility product of 10^-39. Any ideas?

**Organic Chemistry**

When I solve for Fe I get 1.75mL and for SYL I get 210mL. That can't be correct if we are trying to make 50mL. The equation is: Salicylic Acid + [Fe(H2o)6]^+3 ---> Iron-salicylate complex

**Grade 12 Calculus and Vectors**

Thank you very much Steve.

**Grade 12 Calculus and Vectors**

A homeowner wants to enclose a rectangular garden with fencing The garden will be adjacent to his neighbours lot. There will be fencing on all four sides. His neighbour will be paying for half of the shared fence. What should the dimensions of the garden be if the area is 432 ...

**Pre-Calculus**

Okay, what point is your origin? Normally it is (0,0) but not always...

**Math**

no C.

**math**

5C3 = 10

**math**

substituting -x + 13 = x² + 6 x + 7 0 = x² + 7 x - 6 none of the answers are correct

**Math**

.25 t = 1 t = 1 / .25

**math**

A - 25 = B + 25 ... A - 50 = B 7(B - 100) = 2(A + 100) ... 7 B - 700 = 2 A + 200 ... 7 B = 2 A + 900 substituting ... 7(A - 50) = 2 A + 900 ... 7 A - 350 = 2 A + 900 ... 5 A = 1250 ... A = 250

**SCIENCE**

pressure is force per unit area 100 N / 25 cm² = 4 N/cm² the SI pressure unit is the pascal 4 N/cm² = 40000 N/m² = 4 kPa

**Maths -Logarithm**

3^3 = 27 log(x) = 27 log(3) x = 10^[log(x)]

**geometry**

hard to tell without the diagram

**algebra**

(a) 37% / 60% (b) 37% / 52%

**Physics**

momentum is conserved m bt * v bt = (m bt + m bk) * v bkbt h = ½ g t² ... 1.3 = 4.9 t² ... t = .52 s v bkbt = d / t = 2.2 m / .52 s ... v bkbt = 4.2 m/s 7 * v bt = 131 * 4.2

**probability help!!**

all wait times have an equal probability so the probability of being in any one of three five-minute intervals is ⅓ (a) is the 1st interval (b) is the last interval

**Math**

the slant height is the height of the triangles that make up the sides of the pyramid the base of the triangles is the base side length pentagonal means five triangular sides with a height of 18 and a base of 9 find the areas and add them up (or find one and multiply by 5)

**math**

a = 6350 [1 + (.14 / 2)]^[12 / (1/2)]

**physics**

the acceleration is ... 2 m/s / 14 s = .14 m/s² as the car goes up a slope, the gravitational acceleration on the car is proportional to the sine of the angle of the slope sin(Θ) = .14 m/s² / 9.8 m/s² = .014 Θ = 0.8º

**Math**

Given function 3x/x^2-x-12 sub in -1 for x. I get the value x=0.3. Is that right?

**ph science**

work = 64 N * cos(35º) * 45 m

**Physics**

A 0.11-kg balloon is filled with helium (density = 0.179 kg/m3). If the balloon is a sphere with a radius of 5.4 m, what is the maximum weight it can lift?

**Algebra**

A man paid $7.80 for 5 The grams of peanuts and 3 kg of walnuts. Walnuts are $.20 a kilogram more than peanuts how much did she pay per kilogram for each

**home school**

In which of the following are 1/2,5/6, and 5/8 arranged in ascending order?

**Math Question**

Write the fraction below as a decimal. 7 --- = 100

**phy 231**

at the equilibrium position, there is no energy stored in the spring, it's all in the kinetic energy of the block KE = 1/2 m v²

**Physics**

vertical ... 2[5 sin(θ)] / g = t ... h = 5/2 sin(θ) * t/2 horizontal ... d = 5 cos(θ) t 2h = d 5/2 sin(θ) t = 5 cos(θ) t dividing by cos(θ) t and multiplying by 2/5 tan(θ) = 2 substitute back to find t

**Physics**

time up equals time down flight time = 2 * 30 m/s / 10 m/s²

**Physics**

there are 3600 s in an hr 180 km/h = 50 m/s the average velocity during the stop is ... (50 + 0) / 2 the stopping distance is ... 25 m/s * 20 s

**Physics**

gravity decelerates the ball time to peak is ... 30 / 9.8 the velocity at peak is zero, so the average velocity is ... (30 + 0) / 2 peak height is average velocity, multiplied by time

**Physics**

it's a 3-4-5 triangle 600-800-?

**Math**

If a pie was cut into sixths and one cut into eighths how many pieces are there altogether?

**Statistics**

the upper 15% of weights are a little over one S.D. above the mean so, more than ... 764 + 33 using a z-score table ... 1.036 S.D so, more than ... 764 + (33 * 1.036)

**Chemistry**

-log[H⁺] = 5.42 ... [H⁺] = 10^-5.42 = 3.80E-6 Ka = [H⁺][A⁻] / [HA] ... = 3.80E-6 * 3.80E-6 / ... (.095 - 3.80E-6) ... = ?

**Science**

electricity

**Physics**

momentum = m v = .057 * 29 the units are kg·m/s

**Algebra**

completing the square (16 / 2)² = 64 (x + 8)²

**Chemistry 101**

400 T * 1.0 oz/T * $1625 / oz

**Math**

s^2 = (6/2)^2 + 5^2 pick another letter

**Geometry**

factor the numerator [n * (n + 1)] / 4 n cancel the n in the numerator and denominator (n + 1) / 4

**physics**

conservation of momentum (again) (2300 + 1290) * 4800 = (1290 * 5600) + (2300 * v)

**physics**

momentum is conserved (a) 98 * 3.2 = 235 * -v (b) 98 * 3.2 = (98 + 235) * v

**Algebra 2**

you have the hypotenuse and the side lengths use trig functions to find the two unknown angles (A and B) S-O-H-C-A-H-T-O-A

**MATHS**

7 P + 22 = 2 (5 P + 2) 7 P + 22 = 10 P + 4 18 = 3 P

**STATISTIC**

you are right

**Physics**

the car is overtaking the truck the relative speed is 30 mph ... the distance is closing ... that's why the Doppler frequency is higher apparent frequency = actual frequency * [(speed of sound) / (speed of sound - closing speed)]

**physics**

f = m a μ m g = m (d / t²) μ = (d / t²) / g = (1320 / 6²) / 32 the assumption is that all of the mass acts on the driving wheels

**math**

Solve for all real values of y: |3y+7|=|2y-1|.

**physics**

when it leaves the roof vertical velocity ... -7.00 sin(40º) horizontal velocity ... 7.00 cos(40º) the horizontal velocity is constant the vertical velocity is increased by gravity (acceleration) h = -1/2 g t² + v₀ t + h₀ ... t is the time of flight ...

**physics**

m g h = 1/2 m v² h = v² / (2 g)

**Physics**

the drop height is ... 1/2 g t² the times are ... 4 s ... and (4 - 2.34) s g is ... 9.81 m/s² fire up that calculator

**Trig**

a road is inclined at an angle of 45degrees. After driving 300 feet along this road, find the driver's increase in altitude.

**Ms. Sue, please help me on math!**

they are both correct

**Physics**

an Ampere is a Coulomb per second a Coulomb is the charge on 6.242 x 10¹⁸ electrons there are 3600 seconds in an hour .497 * 6.242E18 * 3.6E3 = answer

**Algebra**

they each do a fraction of the job the fractions add to one the whole job (2.2 / T) + (2.2 / J) = 1 substituting [2.2 / (J + 2)] + (2.2 / J) = 1 solve for J, add 2 to find T

**Chemistry**

yes, but they give you the wavelength e = h c / λ make sure your units are consistent

**Chemistry**

2 moles of Al to 3 moles Cl₂ use the molar masses to find the number of moles

**physics**

the decimal point on the mass units is incorrect Joules uses kilograms, not grams you used kg in the momentum, but not the K

**Physics**

in the vertical direction ... h = 1/2 g t^2 + 59 sin(32º) t in the horizontal direction ... d = 59 cos(32º) t use the axis of symmetry of the parabola to find the time for max height plug the time into the vertical equation to find the max height the initial energy ...

**physics**

momentum is conserved 71 * 2.5 = 59 * v the direction is negative x

**chemistry**

the molar mass of water is 18.0 g E = [25 * (100 - 25) * .00418] + ... [(25 / 18) * 40.6]

**science, chemistry**

100.0 mL * 12.0 M = v * 5.20 M

**Math**

7 * 1/12

**6th grade math median range mode**

if all the values occur equally, there is no mode

**Physics**

the acceleration is ... (5.31 - 1.25) / 1.05 the sine of the angle of inclination is equal to the actual acceleration divided by gravitational acceleration sin(Θ) = [(5.31 - 1.25) / 1.05] / g

**Algebra**

z + t + c = 1000 t = 2 z c = 15 t + 10 = 30 z + 10 z + 2z + 30z + 10 = 1000 solve for z, then substitute back to find c and t

**Chemisty**

a mole is Avogadro's number ... 6.02 x 10^23 so you need the mass of a third of a mole of F₂ the molar mass of F₂ is 38 g

**Math question/help please!**

the letters correspond to the vertices K and P are congruent as are M and R and L and Q MK and ML are sides ...not measured in degrees just post the size of any of the angles that are given

**science**

this is a time/temperature plot the line slopes up from 35 to 75 while the solid warms up the line levels off at 75 while the solid melts phase change the line slopes up from 75 to 126 while the liquid warms up the line levels off at 126 while the liquid boils phase change the...

**Chemistry**

sorry...should be 2 H₂

**Chemistry**

Ca is a +2 ion so 2 OH (just like the 2 H) CaH₂ + 2 H₂O --> Ca(OH)₂ + H₂

**Physics**

gravitational potential energy is converted to kinetic energy m g h = 1/2 m v² 9.8 * 1.8 = v² / 2

**physics**

the vertical launch velocity is ... 33 sin(12º) 0 = 1/2 g t² + [33 sin(12º)] t + 23 use the quadratic formula to find t ...you want the positive solution g = 9.8 m/s²

**chemistry**

the spectrum is the result of hydrogen's electron transitioning between energy levels the levels are fixed ... quantized (per bob)

**Chemistry: stoich**

molar mass of O₂ is 32 g 5 moles O₂ yields 4 moles H₂O

**Chemistry**

answered

**physics**

momentum is conserved x-component ... -8.80 [4720 / (4720 + 1180)] y-component ... -1.45 [1180 / (1180 + 4720)] v = √(x^2 + y^2) the tangent of the reference angle in quad III is ... y/x

**Chemistry**

the molar mass of O₂ is 32 g 3 moles of oxygen produce 2 moles of iron oxide (2.50 / 32)* 2/3 = moles of Fe₂O₃ the molar mass of Fe₂O₃ is 159.7 g

**Math HELPP!!**

obtuse? that means an angle greater than 90º B is correct

**Math HELPP!!!!**

correct

**Math. PLZZZ HELP ME!!!**

or B or C... not enough info in the question TOO GENERAL

**Math. PLZZZ HELP ME!!!**

a quadrilateral with opposite sides equal and parallel is a parallelogram the 1st three answers are various types of parallelograms a trapezoid is not

**Science**

the same side of the moon always faces the Earth because the moon's rotational period is equal to its orbital period if the moon had a rotational period different from its orbital period, then different sides of the moon would be facing the Earth at different times