• ### Height in Centimetres (Rounded to the nearest CM without a decimal point)?

Are you kidding?
Are you kidding?
8 answers · Mathematics · 10 hours ago
• ### C2H4 +[O] +H2O=C2H6O2 34.5 kg of ethane were converted into 57.6 kg of ethane 1,2 diol Calculate the percentage yield?

Molar mass of ethane is 24 + 4.06 = 28.06. Molar mass of C2H6O2 is 24 + 6.09 + 32 = 62.09. (34.5 kg)*(62.09/28.06) = 76.34; finally, 57.6/76.34 = 75.5%.
Molar mass of ethane is 24 + 4.06 = 28.06. Molar mass of C2H6O2 is 24 + 6.09 + 32 = 62.09. (34.5 kg)*(62.09/28.06) = 76.34; finally, 57.6/76.34 = 75.5%.
1 answer · Chemistry · 10 hours ago
• ### Modeling Multistage Modules ferrotec | Ferrotec-Nord.com?

not a math question
not a math question
3 answers · Mathematics · 11 hours ago
• ### Does ammonium react with oxygen ?

"Ammonium" is a radical (NH4). Maybe you meant "ammonia." ?? Ammonium oxide and ammonium hydroxide both exist, and their properties are extensively discussed in a 1953 paper by Hildenbrand and Giauque which is easy to find on the Internet. Ammonia (NH3) can be burned in air if the mixture proportions are just right. show more
"Ammonium" is a radical (NH4). Maybe you meant "ammonia." ?? Ammonium oxide and ammonium hydroxide both exist, and their properties are extensively discussed in a 1953 paper by Hildenbrand and Giauque which is easy to find on the Internet. Ammonia (NH3) can be burned in air if the mixture proportions are just right.
2 answers · Chemistry · 11 hours ago
• ### Chem help, stoichiometry!!?

Ca(OH)2 + CO2 --> H2O + CaCO3. The molar mass of CO2 is 12 + 32 = 44.0. The molar mass of H2O is 18.015. So the answer is (5.9 tons)*(18.015/44.0) = about 2.4 tons of water, or 4800 pounds of water or 2177.24 kg of water. At 20C, the density of water is 998.2 kg/m^3, so the volume would be 2.18 m^3, about 2180 liters of water. show more
Ca(OH)2 + CO2 --> H2O + CaCO3. The molar mass of CO2 is 12 + 32 = 44.0. The molar mass of H2O is 18.015. So the answer is (5.9 tons)*(18.015/44.0) = about 2.4 tons of water, or 4800 pounds of water or 2177.24 kg of water. At 20C, the density of water is 998.2 kg/m^3, so the volume would be 2.18 m^3, about 2180 liters of water.
2 answers · Chemistry · 11 hours ago
• ### Find the centroid of the region lying underneath the graph of the function over the given interval.?

As a reality check on Captain Matticus's answer, I'll calculate the numerical values of his answer. When I EYEBALL the graph of (1 + x^2)^(-1/2) on [0,8], it looks like the centroid should be x-bar = 2 or 3 and y-bar = 1/4 or 1/3. The values of CM's answers are x-bar = 2.544 and y-bar = 0.2605. Yup, that makes perfect sense !!! show more
As a reality check on Captain Matticus's answer, I'll calculate the numerical values of his answer. When I EYEBALL the graph of (1 + x^2)^(-1/2) on [0,8], it looks like the centroid should be x-bar = 2 or 3 and y-bar = 1/4 or 1/3. The values of CM's answers are x-bar = 2.544 and y-bar = 0.2605. Yup, that makes perfect sense !!!
2 answers · Mathematics · 12 hours ago
• ### Determine the mass of copper that has the same number of atoms as there are in 9.39 mg of potassium?

Atomic masses: potassium 39.10, copper 63.55; so the answer is (9.39 mg)(63.55/39.10) = about 15 mg but use a calculator.
Atomic masses: potassium 39.10, copper 63.55; so the answer is (9.39 mg)(63.55/39.10) = about 15 mg but use a calculator.
1 answer · Chemistry · 18 hours ago
• ### How do I find centripetal acceleration with only the mass and radius?

The centripetal force is the product of the mass and the centripetal acceleration. (Good old F = ma.)
The centripetal force is the product of the mass and the centripetal acceleration. (Good old F = ma.)
3 answers · Physics · 19 hours ago
• ### Can u tell me what is 7/9 divided by 1/6 or 7/9 * 6/1?

42/9 = 14/3, or 4 2/3.
42/9 = 14/3, or 4 2/3.
5 answers · Mathematics · 19 hours ago
• ### Do ASL Interpreters get paid hourly?

Working conditions and pay are set by contracts with particular employers, not by occupation. It seems unlikely, though, that the person would be given the full pay for the third hour.
Working conditions and pay are set by contracts with particular employers, not by occupation. It seems unlikely, though, that the person would be given the full pay for the third hour.
2 answers · Mathematics · 19 hours ago
• ### An 88 kg skydiver jumps out of an airplane at an altitude of 1198 m and opens the parachute at an altitude of 132 m.?

Gravitational force is (9.8 m/s^2)(88 kg) = 862.4 N. Let's take the given retarding forces at face value, even though the notion that the force with the parachute open would exceed the gravitational force could not possibly be true if the diver were not already moving downward very fast. In the first 1066 meters of falling, the diver's... show more
Gravitational force is (9.8 m/s^2)(88 kg) = 862.4 N. Let's take the given retarding forces at face value, even though the notion that the force with the parachute open would exceed the gravitational force could not possibly be true if the diver were not already moving downward very fast. In the first 1066 meters of falling, the diver's downward acceleration is 9.8 m/s^2 - 49N/(88 kg) = 9.2432 m/s^2, so his speed when he opens the parachute is sqrt(2*a*d) = sqrt(2*1066*9.2432) = 140.38 m/s. After opening the parachute, the diver accelerates upward by (3426 N)/(88 kg) - 9.8 m/s^2 = 29.132 m/s^2. So his speed when he hits the ground is found from 2*29.132*132 = 140.38^2 - vf^2 => vf = sqrt(12015.7) = 109.6 m/s (downward).
2 answers · Physics · 19 hours ago
• ### A small piece of wood is dropped from a height 4.2m above water. The wood has density 830 kg/m^3 while the water s density is 1000 kg/m^3?

This is not a question.
This is not a question.
1 answer · Physics · 23 hours ago
• ### What value of θ will maximize the trough's volume?

The height of the trough is 9*cos(theta). The horizontal leg of each small triangle is 9*sin(theta). The area of the rectangle is 36*cos(theta). The area of the two small triangles together is 81*sin(theta)*cos(theta) or 40.5*sin(2*theta). The total cross-sectional area of the trough is A = 36*cos(theta) + 40.5*sin(2*theta). dA/d(theta) =... show more
The height of the trough is 9*cos(theta). The horizontal leg of each small triangle is 9*sin(theta). The area of the rectangle is 36*cos(theta). The area of the two small triangles together is 81*sin(theta)*cos(theta) or 40.5*sin(2*theta). The total cross-sectional area of the trough is A = 36*cos(theta) + 40.5*sin(2*theta). dA/d(theta) = -36*sin(theta) + 81*cos(2*theta). Setting this expression to 0, we get 36*sin(theta) = 81*cos(2*theta) => 4*sin(theta) = 9*[cos^2(theta) - sin^2(theta)] => 4*sin(theta) = 9*[1 - 2*sin^2(theta)] => 18*sin^2(theta) + 4*sin(theta) - 9 = 0. Using the quadratic formula, you have sin(theta) = -1/9 +/- (1/36)*sqrt(16+648) = +0.60467. theta = 37.2 degrees. To see that this makes SOME sense, note that if theta = 45 degrees, the cross-section area is 81/2 + 18*sqrt(2) = about 66; if theta = 30 degrees, the cross-section area is 81*sqrt(3)/4 + 18*sqrt(3) = about 66.25; but if theta = 36.87 degrees (giving 3-4-5 triangles), the area is 972/25 + 3.2*9 = around 67.68...i.e., a little bigger than what you get for theta = 30 or 45.
3 answers · Mathematics · 23 hours ago
• ### What are the zeros of the equation -3x^4+27x^2+1200=0?

Let u = x^2, you have -3u^2 + 27u + 1200 = 0 => u^2 - 9u - 400 = 0 => (u - 25)(u + 16) = 0 => u = 25 or -16, so x is either +/-5 or +/-4i. Probably they want the "real" zeros, so that would be the +/- 5.
Let u = x^2, you have -3u^2 + 27u + 1200 = 0 => u^2 - 9u - 400 = 0 => (u - 25)(u + 16) = 0 => u = 25 or -16, so x is either +/-5 or +/-4i. Probably they want the "real" zeros, so that would be the +/- 5.
4 answers · Mathematics · 23 hours ago
• ### Are we alone in the universe? And do you think they might’ve visited Earth? Why? Or why not?

Not alone in the universe. The probability that any extraterrestrial species has visited the earth is very close to zero, but we can never know for sure.
Not alone in the universe. The probability that any extraterrestrial species has visited the earth is very close to zero, but we can never know for sure.
11 answers · Astronomy & Space · 24 hours ago
• ### What is this math called? It has letters and numbers x/a+y/b=6?

It's called algebra! Usually starts around grade 8, but the question you're asked in this example is not suitable for "algebra 1" and would more likely come up in "algebra 2." You can picture the given line as sloping down from left to right. It would cross the y-axis at the point (0,6b) and the x-axis at the point... show more
It's called algebra! Usually starts around grade 8, but the question you're asked in this example is not suitable for "algebra 1" and would more likely come up in "algebra 2." You can picture the given line as sloping down from left to right. It would cross the y-axis at the point (0,6b) and the x-axis at the point (6a,0). The point closest to the origin would be on a line perpendicular to the given line. The slope of that perpendicular line would be the negative reciprocal of the slope of the given line. The slope of the given line is -b/a, so the slope of the perpendicular would be +a/b, and the equation of the perpendicular line (through the origin) would be by = ax. So now there are two equations to solve simultaneously: by = ax and x/a + y/b = 6. Substituting ax/b for "y" the 2nd eqn becomes: x/a + ax/b^2 = 6 => xb^2 + x = 6b^2/a => x = 6b^2/[a(1 + b^2)], and y = ax/b = 6b/(1 + b^2). Those are the coordinates of the desired point. You should check through my work and make sure that it makes sense to you, and also check for any minor mistake I might have made !
6 answers · Mathematics · 24 hours ago
• ### Evaluate the integral geometrically in terms of area. Given Function is (3x - 2)dx?

Area of the small triangle is (1/2)(4/3)(4) = 8/3. Area of the large triangle is (1/2)(8/3)(8) = 32/3. Integrated area is 8/3 - 32/3 = -24/3 = -8.
Area of the small triangle is (1/2)(4/3)(4) = 8/3. Area of the large triangle is (1/2)(8/3)(8) = 32/3. Integrated area is 8/3 - 32/3 = -24/3 = -8.
3 answers · Mathematics · 24 hours ago
• ### A projectile I shot downward from the top of a surface that is 110 meters tall.?

s = 110m - (120 m/s) * t - (1/2)gt^2; hits the ground in something like 0.8847 seconds.
s = 110m - (120 m/s) * t - (1/2)gt^2; hits the ground in something like 0.8847 seconds.
3 answers · Physics · 1 day ago
• ### Help with physics?

(a) Magnitude of F1 = G(2.00 kg^2)/(10.0 m)^2; magnitude of F3 = G(6.00 kg^2)/(10.0 m)^2. Magnitude of their vector sum is the magnitude of G(kg^2/(10.0m)^2) * [2.00i + 3.00j + 3*sqrt(3)i/2] = G(kg^2/(10.0m)^2) times the square root of (4 + 6*sqrt(3) + 27/2 + 9) = G(kg^2/(10.0m)^2)*sqrt(36.892) = 4.05 x 10^(-12) N. (b) If we take the "x"... show more
(a) Magnitude of F1 = G(2.00 kg^2)/(10.0 m)^2; magnitude of F3 = G(6.00 kg^2)/(10.0 m)^2. Magnitude of their vector sum is the magnitude of G(kg^2/(10.0m)^2) * [2.00i + 3.00j + 3*sqrt(3)i/2] = G(kg^2/(10.0m)^2) times the square root of (4 + 6*sqrt(3) + 27/2 + 9) = G(kg^2/(10.0m)^2)*sqrt(36.892) = 4.05 x 10^(-12) N. (b) If we take the "x" direction to be the direction from the 2.00 kg mass to the 1.00 kg mass, the direction of the net force is arctan[3/(2 + 3*sqrt(3)/2)] = 33.12 degrees; i.e., about 26.88 degrees away from the direction from 2.00 kg mass to 3.00 kg mass.
1 answer · Physics · 1 day ago
• ### If 7 trumpets played together, then the combined sound level (in dB) would be how much?

Best answer: log_10(7) = 0.8451, so the level would be 105.5 dB + 8.451 dB = about 114 dB.
Best answer: log_10(7) = 0.8451, so the level would be 105.5 dB + 8.451 dB = about 114 dB.
2 answers · Physics · 1 day ago