Friday

October 24, 2014

October 24, 2014

Total # Posts: 350

**physcs **

Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be 41.8 km/s and 64.6 km/s. The slower planet's orbital period is 8.84 years. (a) What is the mass of the star? (b) What ...
*October 21, 2014*

**guidance**

yes, it is B
*October 20, 2014*

**guidance**

it is aggression, you can't kick others, take it from that principle.
*October 20, 2014*

**Physics**

Got it: reasoning and solution.. the normal force exerted by the wall on each astronaut is the centripetal force needed to keep him in the circular path so, Fc=mv^2/r. rearranging and letting Fc=(1/3)mg yields r=3v^2/g= 3(29.1m/s)^2/(9.8m/s^2)=259m
*October 20, 2014*

**Physics **

Suppose the surface (radius = r) of a cylindrical space station is rotating at 29.1 m/s to provide artificial gravity. What must be the value of r for the astronauts to weigh 1/3 of their earth weight? Don't know how to start please help.
*October 20, 2014*

**physics**

I was able to solve this problem at firs, use the equation V=sqrt(R g tan theta) since you have two angles you will need to separate the equation into 2 Va= sqrt(r g tan a theta) Vb= sqrt (r g tan b theta) then solve for Vb Vb/Va= sqrt(r g tanb )/ sqrt(r g tan a theta) r and g...
*October 20, 2014*

**physics **

Curve A is banked at 11.2 °, and curve B is banked at an angle of 15.2 °. A car can travel around curve A without relying on friction at a speed of 14.5 m/s. At what speed can this car travel around curve B without relying on friction? Do I need to find radius in ...
*October 20, 2014*

**physics**

Thank you Don. A great way of clarifying through the steps, very detail oriented. Thanks again!
*October 20, 2014*

**physics **

Car A uses tires for which the coefficient of static friction is 0.333 on a particular unbanked curve. The maximum speed at which the car can negotiate this curve is 13.8 m/s. Car B uses tires for which the coefficient of static friction is 0.843 on the same curve. What is the...
*October 20, 2014*

**physics**

Thanks a lot Damon!
*October 12, 2014*

**physics **

A ball is dropped from rest at the top of a 5.89-m-tall building, falls straight downward, collides inelastically with the ground, and bounces back. The ball loses 5.34% of its kinetic energy every time it collides with the ground. How many bounces can the ball make and still ...
*October 12, 2014*

**CHEMISTRY**

As far as I know, Delta T means the difference in temperature. T final- T initial.
*October 12, 2014*

**physics**

ok I got the answer: a) Vf1=(m1-m2/m1+m2)*(Vi1) B) Vf2=[(2(m1)/m1+m2](Vi1)
*October 12, 2014*

**physics**

sorry I solved part C, I need help with a and b pls.
*October 12, 2014*

**physics**

A 2.20-kg ball, moving to the right at a velocity of +1.27 m/s on a frictionless table, collides head-on with a stationary 7.20-kg ball. Find the final velocities of (a) the 2.20-kg ball and of (b) the 7.20-kg ball if the collision is elastic. (c) Find the magnitude and ...
*October 12, 2014*

**physics **

A 220-kg log is pulled up a ramp by means of a rope that is parallel to the surface of the ramp. The ramp is inclined at 26.6° with respect to the horizontal. The coefficient of kinetic friction between the log and the ramp is 0.863, and the log has an acceleration of 0....
*October 1, 2014*

**physics**

I figured this out.. So basically you find the acceleration first V-Vo/t= 59.4-0/14.1 = 4.21m/s2 then, you find the apparent weight by multiplying 66.7*(9.8 + 4.21)= 934.47N
*September 30, 2014*

**physics**

A rocket blasts off from rest and attains a speed of 59.4 m/s in 14.1 s. An astronaut has a mass of 66.7 kg. What is the astronaut's apparent weight during takeoff?
*September 30, 2014*

**Math**

and theta is between 0< theta< 2 pi
*September 29, 2014*

**Math**

solve: cot(2theta/3)= -sqrt3 Please help, I don't know how to start and how to set it up.
*September 29, 2014*

**physics**

A rocket blasts off from rest and attains a speed of 59.4 m/s in 14.1 s. An astronaut has a mass of 66.7 kg. What is the astronaut's apparent weight during takeoff?
*September 28, 2014*

**physics**

Damon, I honestly want to thank you for your precious efforts in helping students. I have a question regarding the equations you've set above. Could you clarify how to find FB please?
*September 27, 2014*

**physics**

The mass of a robot is 6930 kg. This robot weighs 2520 N more on planet A than it does on planet B. Both planets have the same radius of 3.01 × 106 m. What is the difference MA - MB in the masses of these planets?
*September 27, 2014*

**physics**

A ball is thrown upward at a speed v0 at an angle of 59.0¢ª above the horizontal. It reaches a maximum height of 7.5 m. How high would this ball go if it were thrown straight upward at speed v0?
*September 20, 2014*

**physics**

thank you very much Damon. It is much clear now, since u explained it step by step.
*September 19, 2014*

**physics**

An airplane with a speed of 85.3 m/s is climbing upward at an angle of 45.0 ° with respect to the horizontal. When the plane's altitude is 587 m, the pilot releases a package. (a) Calculate the distance along the ground, measured from a point directly beneath the point...
*September 19, 2014*

**physics- HELP**

An airplane with a speed of 85.3 m/s is climbing upward at an angle of 45.0 ° with respect to the horizontal. When the plane's altitude is 587 m, the pilot releases a package. (a) Calculate the distance along the ground, measured from a point directly beneath the point...
*September 19, 2014*

**physics**

An Olympic long jumper leaves the ground at an angle of 18.7 ° and travels through the air for a horizontal distance of 7.04 m before landing. What is the takeoff speed of the jumper?
*September 19, 2014*

**physics**

An airplane with a speed of 85.3 m/s is climbing upward at an angle of 45.0 ° with respect to the horizontal. When the plane's altitude is 587 m, the pilot releases a package. (a) Calculate the distance along the ground, measured from a point directly beneath the point...
*September 19, 2014*

**physics**

A tennis ball is struck and departs from the racket horizontally with a speed of 26.4 m/s. The ball hits the court at a horizontal distance of 18.4 from the racket. How far above the court is the tennis ball when it leaves the racket?
*September 15, 2014*

**Math**

Lola is placing appetizers on plates She has 63 spring rolls and 84 cheese cubes She wants to include both appetizers on each plate Each plate must have the same number of spring rolls and cheese cubes. What is the greatest number of plates she can make using all of the ...
*September 15, 2014*

**physics**

A tennis ball is struck and departs from the racket horizontally with a speed of 26.4 m/s. The ball hits the court at a horizontal distance of 18.4 from the racket. How far above the court is the tennis ball when it leaves the racket?
*September 15, 2014*

**physics**

A tennis ball is shot vertically upward in an evacuated chamber inside a tower with an initial speed of 20.0 m/s at time t = 0 s. Approximately how long does it take the tennis ball to reach its maximum height?
*September 13, 2014*

**physics **

The depth of the ocean is sometimes measured in fathoms (1 fathom = 6 feet). Distance on the surface of the ocean is sometimes measured in nautical miles (1 nautical mile = 6076 feet). The water beneath a surface rectangle 3.70 nautical miles by 2.80 nautical miles has a depth...
*September 13, 2014*

**physics**

The depth of the ocean is sometimes measured in fathoms (1 fathom = 6 feet). Distance on the surface of the ocean is sometimes measured in nautical miles (1 nautical mile = 6076 feet). The water beneath a surface rectangle 3.70 nautical miles by 2.80 nautical miles has a depth...
*September 13, 2014*

**physics **

The depth of the ocean is sometimes measured in fathoms (1 fathom = 6 feet). Distance on the surface of the ocean is sometimes measured in nautical miles (1 nautical mile = 6076 feet). The water beneath a surface rectangle 3.70 nautical miles by 2.80 nautical miles has a depth...
*September 13, 2014*

**chem**

Thank you Dr. Bob
*September 11, 2014*

**chem**

If 309 J of heat are removed from 10.0 g of ice (specific heat = 2.06 J/g ºC) at -5.5 ºC, what is the final temperature of the ice sample?
*September 11, 2014*

**physics**

A car is traveling along a straight road at a velocity of +27.7 m/s when its engine cuts out. For the next 1.94 seconds, the car slows down, and its average acceleration is . For the next 4.92 seconds, the car slows down further, and its average acceleration is . The velocity ...
*September 9, 2014*

**physics**

A race driver has made a pit stop to refuel. After refueling, he starts from rest and leaves the pit area with an acceleration whose magnitude is 5.4 m/s2; after 4.4 s he enters the main speedway. At the same instant, another car on the speedway and traveling at a constant ...
*September 7, 2014*

**physics**

Two rockets are flying in the same direction and are side by side at the instant their retrorockets fire. Rocket A has an initial velocity of +4100 m/s, while rocket B has an initial velocity of +9400 m/s. After a time t both rockets are again side by side, the displacement of...
*September 7, 2014*

**physics**

thanks Demon
*September 7, 2014*

**physics**

In getting ready to slam-dunk the ball, a basketball player starts from rest and sprints to a speed of 11.0 m/s in 2.58 s. Assuming that the player accelerates uniformly, determine the distance he runs.
*September 7, 2014*

**Algebra 2**

4t-3s^2+s^3 for t=-2 and s=-3 4(-2)-3(-3)^2+(-3)^3 -8-3(-9)+(-27) -8-(-27)+(-27)=-8 Am I right?
*September 3, 2014*

**Probability**

In a random sample of students at a middle school, 24 wanted to change the mascot, and 30 wanted to keep the current mascot. Which is the best prediction for how many of the total of 1,140 students want to keep the current mascot? (a) 507 (b) 600 (c) 633 (d) 950
*July 24, 2014*

**Chemistry **

Benzene sulfonic acid, C6H5SO3H, is a strong acid and will neutralise sodium hydroxide solution (a 1:1 molar ratio). Benzene sulfonic acid crystals (y grams) were weighed into a titration flask and titrated against sodium hydroxide solution (1.0 M) and needed a volume of 26.2 ...
*June 15, 2014*

**Maths**

1. What is the Right Riemann Sum for f(x)=x−3 over the interval [8,11], with n=3 rectangles of equal width? 2. What is the right Riemann sum of f(x)=x+3 when using 3 rectangles in the range [−3,−1]? 3. What is the left Riemann sum of f(x)=−2x+1 when ...
*June 1, 2014*

**Math**

A rectangular rug has a base b and a height h, with a perimeter of 30 feet. Both b and h are both whole numbers between 5 and 10 feet. Fill in the blanks to complete this sentence: The area of the rug is at least _______ but not greater than ______.
*May 29, 2014*

**statistics**

Phil is right, the answer is B
*April 27, 2014*

**business Math**

Rate= interest / principal*time interest = 15 Principal =100 Time is 2/52 (2 weeks/ 52 weeks/year) 15/(100*2/52)= 3.90 3.90*100 = 390%
*April 2, 2014*

**physics**

a glass lens has a convex surface with a radius 25.0 cm and a concave surface with radius 50.0 cm with the glass refraction = 1.51 calculate the focal length
*March 30, 2014*

**Help!! Physics**

What capacitance in needed in series with an 785 µH inductor to form a circuit that radiates a wavelength of 199 m?
*March 29, 2014*

**English/Social Studies**

I have checked some of these sites and while it gives me the pros and cons, I don't see a reason why or how implementing this program will affect us economically?
*March 26, 2014*

**English/Social Studies**

I'm writing an essay and need help coming up with economic reasons to to be against Caps on Punitive Damages. Google is not turning up what I need. I need how will implementing this program be bad economically?
*March 26, 2014*

**Calculus**

Find the limit. lim 5-x/(x^2-25) x-->5 Here is the work I have so far: lim 5-x/(x^2-25) = lim 5-x/(x-5)(x+5) x-->5 x-->5 lim (1/x+5) = lim 1/10 x-->5 x-->5 I just wanted to double check with someone and see if the answer is supposed to be positive or negative. ...
*January 22, 2014*

**Calculus**

What is the domain of f(x)= (x-3)/(x^2-9)? lim f(x) x->3
*January 18, 2014*

**Language Arts**

Oh okay I get it now. Thank you. :)
*January 14, 2014*

**Language Arts**

Thank you I also was wondering about my answer for this question. *Climbing so slowly they seem immobile* is how sloths spend their days. A. Prepositional Phrase B. Gerund Phrase C. Participial Phrase D. Appositive Phrase My answer is A. Am not sure if it's right or not.
*January 14, 2014*

**Language Arts**

*Trying to laugh as quietly as possible*, Lucas snuck out of the kitchen. A. Prepositional phrase B. Gerund phrase C. Participial phrase D. Appositive phrase Hello I was wondering if my answer is correct for this question, the answer I choose was C. Thanks. :)
*January 14, 2014*

**math**

well aren't you helpful h.
*December 8, 2013*

**Biochem**

Should say absorbancy *, A, was plotted.. My phone autocorrected the word.
*December 6, 2013*

**Biochem **

If the calibration curve for a Beer's Law plot of a protein assay had a slope of 0.433 when absorb acne, A, was plotted as a function of protein concentration, c, in mg/mL. The absorbance of an unknown protein sample was 0.345. What is the concentration of protein in this ...
*December 6, 2013*

**Chem**

If the calibration curve for a Beer's Law plot of a protein assay had a slope of 0.433 when absorb acne, A, was plotted as a function of protein concentration, c, in mg/mL. The absorbance of an unknown protein sample was 0.345. What is the concentration of protein in this ...
*December 6, 2013*

**Science**

A biologist is constructing a cladogram to show the evolutionary relationships between the animals shown below. If anatomical features are used to construct the cladogram, which animal will be placed farthest from the shown animal? Animal shown: connexus. com/content/media/...
*December 5, 2013*

**Science need help**

Not 4; it is an independent variable. I think it is 5 and 6, as the plant that benefits more (either from vinegar or tap water) will have more germinated seeds and the length of the root will increase.
*December 5, 2013*

**Biochemistry**

A protein sample is diluted 5-fold before measuring the protein concentration in a protein assay. In the protein assay, the concentration of the diluted protein is determined to be 0.27 mg/mL. What is the concentration of the original protein sample?
*November 19, 2013*

**Biochemistry**

BSA stock solution A has a concentration of 3.50 mg/mL. 1.00mL of stock solution A is diluted to a final volume of 5.00mL to prepare solution B. 1.00mL of stock solution B is diluted to a final volume of 5.00mL to prepare solution C. 1.00mL of stock solution C is diluted to a ...
*November 18, 2013*

**Precalc**

Prove: sin2x*sinx/2cosx + cos^2 0 = 1
*November 8, 2013*

**science**

Why is a coyote a poor indicator species What natural zone are each of these cities or areas in? Los Angeles, Palm Springs, Santa Monica Mountains, Catalina, San Francisco, Yosemite.
*October 20, 2013*

**Chemistry**

1.15
*October 10, 2013*

**Chemistry**

Convert the concentration of CoCl2 from 22.0 mg/mL into molarity.
*October 6, 2013*

**Math**

I figured it out. No fraction can appear under a radical.
*September 29, 2013*

**Math**

Thank you! I tried to solve it like this: x^2 + 2y^2 = 8 ( x^2 - y^2 = 1 )2 x^2 + 2y^2 = 8 2x^2 - 2y^2 = 2 3x^2 = 10 x^2 = 10/3 x = ±√(10/3) Any idea as to why my textbook would say that the solution is ±√(30/3)?
*September 29, 2013*

**Math**

Solve the system by substitution or elimination. x^2 + 2y^2 = 8 x^2 - y^2 = 1
*September 29, 2013*

**Geometry**

Use the given plan to write a two-column proof of the Symmetric Property of Congruence. Given: segment AB ≅ segment EF Prove: segment EF ≅ segment AB Plan: Use the definition of congruent segments to write segment AB ≅ segment EF as a statement of equality. ...
*September 17, 2013*

**chemistry**

df
*September 15, 2013*

**chemistry**

An automobile maker has an order for 7,500 new cars to be delivered in one week. Each car must be fitted with a new hood ornament that requires 1 hour and 15 minutes to install. Assuming the factory operates on a standard workweek shift (8 hours per day for 5 days), how many ...
*August 20, 2013*

**STATISTICS**

susie, is b correct?
*August 6, 2013*

**physics**

net torque on the coin, answer not just force balance
*July 28, 2013*

**algebra**

subtract. simplify your answer. 1/6y²+24y - 3/y²-y-20
*June 4, 2013*

**algebra**

the number of calculators mrs. hopkins can buy for the classroom varies inversely as the cost of each calculator. she can buy 24 calculators that cost $60 each. how many calculators can she buy if they cost $80 each?
*May 30, 2013*

**philosophy**

Both Nietzche and Wittgenstein raise the issue of the morality of morality. In other words, they ask "Why should someone be good?" Describe the different ways in which Wittgenstein and Nietzsche understand the human moral predicament i.e. the challenge of asserting ...
*May 14, 2013*

**math**

Giselle has $5.90 dollars in quarters and nickles. If Giselle has 16 more nickles than quarters, how many quarters does Giselle have?
*May 11, 2013*

**Physics**

for problem 1,part 4 (rho_2*g*L^2)/(4*E_1)+(rho_2*g*L^2)/(8*E_2)
*May 5, 2013*

**physics**

for problem 1,part 4 (rho_2*g*L^2)/(4*E_1)+(rho_2*g*L^2)/(8*E_2)
*May 1, 2013*

**physic**

for part 4 (rho_2*g*L^2)/(4*E_1)+(rho_2*g*L^2)/(8*E_2)
*May 1, 2013*

**chemistry**

1.15*10^15
*April 27, 2013*

**Physics**

A spherical shell of radius R carries a uniform surface charge density (charge per unit area) σ. The center of the sphere is at the origin and the shell rotates with angular velocity ω (in rad/sec) around the z-axis (z=0 at the origin). Seen from below, the sphere ...
*April 26, 2013*

**Physics**

A current I=2.3 A flows around a continuous path that consists of portions of two concentric circles of radii a and a/2, respectively, where a=5 cm, and two straight radial segments. The point P is at the common center of the two circle segments. Calculate the components of ...
*April 26, 2013*

**Physics**

The switch in the circuit below has been open for a long, long time, R1=8.0 Ohm, R2=5.0 Ohm, L=0.03 H, V=1 V. The internal resistance of the battery is negligibly small. Determine the currents I1,I2,I3 (in Ampere) in the resistors and in the self-inductor at the moment (a) ...
*April 26, 2013*

**Physics**

Two voltmeters, Vright and Vleft, each with an internal resistance of 106 Ω are connected through wires of negligible resistance (see the circuit below). The “+" side of both voltmeters is up as shown. A changing magnetic field is present in the shaded area. At ...
*April 26, 2013*

**algebra**

find the theoretical probability of each outcome. 1. randomly choosing a day of the week and it is a weekend 4. randomly choosing the letter N from the letters in NUMBER 11. the probability of a thunderstorm is 80%. what are the odds that there will be a thunderstorm?
*April 25, 2013*

**algebra**

how do you make a stem-and-leaf plot for numbers like this: 24,000 28,000 26,000 32,000 30,000 41,000 27,000 22,000 26,000 33,000
*April 22, 2013*

**physics**

Consider the observable M that corresponds to a measurement in the sign basis where the measurement value is 3 if the outcome is + and −2 if the outcome is −. Write M in the standard basis. If M is the Hamiltonian acting on a qubit which is in the state |ψ(0...
*April 19, 2013*

**physics**

Suppose we ran m steps of Grover's algorithm on some function f (which has one marked element y) and the resulting superposition was exactly |y⟩. If we run for m+1 additional steps (i.e. total of 2m+1 steps from the initial state), what is the resulting ...
*April 19, 2013*

**physics**

Consider the Hamiltonian H=Z⊗3 acting on 3 qubits. What is the ground energy of the system? (I.e. the lowest eigenvalue of H?) What is the dimension of the ground energy subspace? (I.e. multiplicity of that eigenvalue?) Which of the following correctly describes the ...
*April 19, 2013*

**chemistry**

A gas absorbs 25kj of heat and does 12kj of work calculate (triangle) E
*April 16, 2013*

**Quantum Physics**

@J No they're right, I misspell the answer
*April 16, 2013*

**Quantum Physics**

@J I input 1/sqrt(K) as 5C's answer, but they are wrong.
*April 16, 2013*