Sunday
January 22, 2017

# Posts by Marco

Total # Posts: 248

Physics
a train is moving at 45km/h when a coupling breaks and the last car separates from the train. as soon as the car separates, the brakes are automatically applied, locking all wheels of the runaway car and causing a uniform decelaration of 5 m/s^2. determine the distance the car...
February 19, 2012

physics
Dolphins emit clicks of sound for communication and echolocation. A marine biologist is monitoring a dolphin swimming in seawater where the speed of sound is 1522 m/s. When the dolphin is swimming directly away at 7.9 m/s, the marine biologist measures the number of clicks ...
December 3, 2011

physics
A member of an aircraft maintenance crew wears protective earplugs that reduce the sound intensity by a factor of 355. When a jet aircraft is taking off, the sound intensity level experienced by the crew member is 72 dB. What sound intensity level would the crew member ...
December 3, 2011

physics
A wave traveling along the x axis is described mathematically by the equation y = 0.15 sin (7.5πt - 0.49πx), where y is the displacement (in meters), t is in seconds, and x is in meters. What is the speed of the wave?
December 3, 2011

physics
A spider hangs from a strand of silk whose radius is 4.40 10-6 m. The density of the silk is 1300 kg/m3. When the spider moves, waves travel along the strand of silk at a speed of 264 m/s. Determine the mass of the spider.
December 3, 2011

math
how do u find the expanded algorithm
November 14, 2011

physics
The drive propeller of a ship starts from rest and accelerates at 3.00 10-3 rad/s2 for 2.05 103 s. For the next 1.75 103 s the propeller rotates at a constant angular speed. Then it decelerates at 2.30 10-3 rad/s2 until it slows (without reversing direction) to an angular ...
November 10, 2011

physics
At the local swimming hole, a favorite trick is to run horizontally off a cliff that is 7.4 m above the water. One diver runs off the edge of the cliff, tucks into a "ball," and rotates on the way down with an average angular speed of 1.6 rev/s. Ignore air resistance...
November 10, 2011

physics
1. Determine the total force acting downwards. Calculate the force of gravity acting on the passenger and the elevator. F = m * a Ft + Fg = 330kg * 3m/s^2 Solve for Ft?
September 30, 2011

MATH
FIND the ESTIMATE: 1) A RARE TRUFFLE ONCE SOLD FO \$13.20 FOR A 0.44 OZ CAN. APPROXIMATELY HOW MUCH WOULD 1LB OF THIS TRUFFLE COST?
September 5, 2011

MATH
i am really confused is this how it should be for the actual cost \$13.20 divide 0.44 oz = 30 x 16 = \$480 for 1 lb for the estimate: \$13 divide by 0.40oz = 32.5 x 16 = \$520 pls advise
September 5, 2011

MATH
i thought i would estimate: 13.20 to 13 and .44 oz to .40 1300 divide by 40 is 32.5 per oz so 16oz equal to 1lb 32.5 x 16 : \$5.20
September 5, 2011

MATH
Ms: Sue need to find th estimate: a rare truffle once sold for \$13.20 for 0.44 oz can approximately how much would 1 lb of this truffle cost? would it be estimate; 13.00 x 0.40 = 32.5 x 16 = 5.20?
September 5, 2011

MATH
FIND EACH ESTIMATE: 1) A RARE TRUFFLE ONCE SOLD FO \$13.20 FOR A 0.44 OZ CAN. APPROXIMATELY HOW MUCH WOULD 1LB OF THIS TRUFFLE COST? 2) THE LENGTH OF THE LONGEST LOAF OF BREAD MEASURED 1,405 FT 1 3/4 IN. IT WAS CUT INTO SLICES 1/2 IN. THICK. HOW MANY SLICES WERE THERE?
September 5, 2011

Physics
Buoyant force= weight of floating object density of liquid * volume of liquid * gravity=weight weight = mass*gravity 1350*.4524*9.81=5991.3594=weight 5991.3594/9.8= mass mass=610.74 N
June 28, 2011

stressed syllables
argument
June 21, 2011

physics
a 0.75 kg mass attached to avertical spring streches the spring 0.30m. what is the spring constant? the mass-spring system is now placed on the horizontal surface and set vibrating. what is the period of the vibration?
March 25, 2011

math
uestion: Five cards are dealt from standard deck of 52 cards, what is the probability of being dealt 3 kings? Here is what I have P(3 kings)= C(4,3) = 3 out of 4 kings being dealt C(48,2 = 2 out of remaning cards to complete 5 card deal C(52,5) = 5 cards dealt out of 52 card ...
March 5, 2011

probabilities
Question: Five cards are dealt from standard deck of 52 cards, what is the probability of being dealt 3 kings? Here is what I have P(3 kings)= C(4,3) = 3 out of 4 kings being dealt C(48,2 = 2 out of remaning cards to complete 5 card deal C(52,5) = 5 cards dealt out of 52 card ...
March 4, 2011

algebra
you have to isolate the variable, so based on that which one is easier to isolate? Y right? So the answer would be y=x+3
March 4, 2011

proabilities
LOL..not very realistic example by the textbook. Would you mind helping understand how you came up with that? which one of the probability formulas was used..I understand the answer just not sure how you came about it. Thanks
March 3, 2011

proabilities
Suppose the NBA has decided to add two more teams to the league. If 18 cities have applied for franchises, what is the probability that in a random drawing, the league selects the two westernmost cities? Having trouble with this one.
March 3, 2011

Math
Thank you!
March 1, 2011

Math
Confused on permutation or combination on this question: A VISA credit card has a first digit of 4 followed by 15 other digits. How many different VISA accounts does this allow? I know the formulas but I am having a hard time determining which one to use. Help!!!
March 1, 2011

Trigonometric Ratios
Right traingle ABC is graphed pm the coordinate plane and has vertices at A(-1,3), B(0,5), and C(4,3). What is the measure of angle C to the nearest degree? F:27 G:29 H:32 J:43
February 14, 2011

Geometry
The hypotenuse if a right triangle measures 9 inches and one of the acute angles measures 36 degress. What is the area if the triangle? Round to the nearest square inch.
February 14, 2011

Geometry
A right triangle has an angle that measures 55 degress. The leg adjacent to this angle has a length of 43 cm. What is the length of the triangle? Round to the nearest tenth
February 14, 2011

Math
thank you!
February 11, 2011

Math
-6≤x/2-4<-3
February 11, 2011

Math
just as it is written: -6 is <or= x/2-4 < -3
February 11, 2011

Math
le is less than or equal and lt is less than..was not sure how to less than equal on the computer
February 11, 2011

Math
I'm stuck on solving this one. If I could get some help please. -6 le x/2 - 4 lt -3
February 11, 2011

math
Stuck on solving this inequality, help please. 3X le 15 and 2x gt -6
February 10, 2011

3 states of matter
hi can you please help me by giving some facts on the 3 states of matter solid liquid gas
January 28, 2011

physics problem
how did u calculate "time to fall". and what is H and g in the equation: sqrt(2 H/g) = 2.86 s?
December 20, 2010

physics problem
A cannon is fired horizontally from atop a 40.0 m tower. The cannonball travels 175 m horizontally before it strikes the ground. With what velocity did the ball leave the muzzle?
December 20, 2010

PHYSICS
is g 9.8 or -9.8?
December 20, 2010

PHYSICS
A cannon is fired horizontally from atop a 40.0 m tower. The cannonball travels 175 m horizontally before it strikes the ground. With what velocity did the ball leave the muzzle?
December 20, 2010

physics
i don't understand your work. please try to explain it more thoroughly.
December 20, 2010

science
hey, check out wiki by yourself. I found a lot of examples
December 5, 2010

math
B--------------C--------A |------6-------|----4----| A = 8
December 5, 2010

math
B--------L--------A |---3----|----3----| 7-4= 3 4-3 = 1 so, B = 1
December 5, 2010

math
B can be -7 or 3
December 5, 2010

math
???What is the question?
December 5, 2010

math
do you mean (âˆš2y)(âˆš3)(âˆš8y) =[(2y)^0.5][(3)^0.5][(8y)^0.5] ??????? If so,it is (âˆš48)y=(4âˆš3)y
December 5, 2010

algebra
....this question have trivial solution m=-3/4 n=-67/8
December 5, 2010

algebra
hey , they are same on both sides. CAN'T solve!
December 5, 2010

Probability
total no. of the combination of two dice = 21 3/21=1/7
December 5, 2010

College physics-oscillations
hey, anyone help???? This is the most difficult question in my assignment and i need to hand in on monday!!!!!!!!!
December 4, 2010

College physics-oscillations
A ball is attached by two spring as shown [vvvOvvv]. If the mass is displaced a distance â–³x BELOW the equilibrium position h (see figure A). Determine whether vertical SHM is possible for the system shown.If so, find the natural frequency. [Assume that the ...
December 4, 2010

Physics
oh, i know why i am wrong.it is because i take friction a wrong direction. thanks very much!(Damon is correct!)
December 4, 2010

Physics
(force exerted by father)+(friction)-weight along the slope = 0 F+(0.2)(35x9.81xcos11)-(35x9.81xsin11)= 0 F= -1.89N (hey, why it is negative? It is wrong. I need more information) work done = F.S
December 4, 2010

Physics
lol, both method can find the answer
December 4, 2010

Physics
At equilibrium position, K.E.=max,P.E. = 0 At the two extreme points, K.E.=0,P.E.=max Total energy is constant at ANY POINT. We find E at extreme point. E = 1/2*k*(0.8)^2 = 0.24J
December 4, 2010

physics
lol, you are welcome
December 4, 2010

physics
K.E. = P.E. 1/2mv^2 = mgh v^2 = 2gh v = (2gh)^(1/2) v = (2x9.81x155)^(1/2) v = 55.146m/s
December 4, 2010

AP Physics
I am a Hong Kong student. But i think i may help you. The only force on the ladder from the wall is the horizontal force.The system here is in static equilibrium. Net torque is zero.Let the total length of the ladder be 1m. then, (1)[(29+9.9+7.1)(g)(0.68)]sinâŠ™...
December 4, 2010

College physics-oscillations
A ball is attached by two spring as shown [vvvOvvv]. If the mass is displaced a distance â–³x BELOW the equilibrium position h (see figure A). Determine whether vertical SHM is possible for the system shown.If so, find the natural frequency. [Assume that the ...
December 4, 2010

Physics
I am a student.But i think i may help you.....the formula for the period of a simple pendulum is T = 2pi(L/g)^0.5.........as you can see..the mass do not affect the period.
December 4, 2010

physical science
what does Q=m times t times c. mean and wat are the meaning of each letter
November 30, 2010

math
thanks!
November 15, 2010

math
having a little trouble following the steps to complete this problem. Rewrite each expression with a positive ration exponent. Simplify if possible: 16^-3/4
November 15, 2010

physical
This is related to physics since it is talking about relativity. The answer is c. Imagine looking out your car window at a bus stop. If you are moving right, the bus stop seems to be moving towards your left. It moves to the left at the same speed as you move to the right. ...
October 30, 2010

english-poetry
thank you
October 16, 2010

english-poetry
I need some help in finding some good one stanza (4 lines) poems. Tried googling but my googling skills are not very good. Maybe one of you have a good list? Thanks
October 16, 2010

physiology
Need help with this one, can't really locate the answer. Consider the bifurcation of a vessel at 20 degrees from the line of blood flow (region a) and a vessel that gives off two vessels at 90 degrees from the main stream of the vessel (region b). Which region is more ...
October 11, 2010

math
Why??
October 6, 2010

biology
What happens to the cells of the body when large quantities of sodium ion were introduced to the blood stream?
September 24, 2010

Science
What happens to the cells of the body when large quantities of sodium ion were introduced to the blood stream? Having trouble with this question, any help please! ;-)
September 23, 2010

math
thanks
September 2, 2010

math
a) 6(2x-3)-5(3x-2) i have -3x-8 b) 8-2[3-5(3x-1)] not sure Thanks
September 2, 2010

math
Not sure of this one. Factor completley 1-81z^2 and this on 16p^2q^2-8pq^2+q^2
May 19, 2010

Math-Factoring
Factor completely. 10x^2yz^2 + 15xy^3z I came up with 5xyz(2xz+3y^2) Correct?
May 19, 2010

Chemistry
Which of the following substances has the greatest solubility in water? A. Ca(OH)2, Ksp = 6.5 × 10-6 B. Ag2SO4, Ksp = 1.5 × 10-5 C. PbI2, Ksp = 7.9 × 10-9 D. Zn(IO3)2, Ksp = 3.9 × 10-6 E. BaF2, Ksp = 1.5 × 10-6
May 2, 2010

Math-Factoring 2
AAAAAAAAAAAAAAAHHHHHHH...thanks..it's in the details.
April 16, 2010

Math-Factoring 2
The last one shold be (x ) (x )
April 16, 2010

Math-Factoring 2
Factor Completely 2x^3-40x^2-192x I have a common factor of x so I rewrote the problem as x(x^2-40x+192) then trying to use FOIL rewrote as (x ) (x ) And that is where i'm stuck.
April 16, 2010

Math - Factoring
Thank you. I am not feeling 100 percent confident in this topic, so you might see a few more, i do appreciate the help!
April 16, 2010

Math - Factoring
Factor Completely 6^8+12x^6-24x^4+30x^2 I got 6x^2(x^6+2x^4-4^2+5) Correct?
April 16, 2010

math
Thanks!
April 15, 2010

math
I am not totally understanding this process. Factor Completely: x^5y^2 - x^4y^2 - 2x^3y^2
April 15, 2010

Algrera
Write the equation of the line passing through the given two points? a) (3,7) and (4,7) Answer: m=7-7/4-3 b) (2,7) and (2,9) Answer: m=9-7/2-2 c) (5,-3) and (1,7) Answer: m=7-(-3)/1-5 Correct?
March 7, 2010

Algrebra
I see it thanks...
March 7, 2010

Algrebra
Write the equation of the line passing through the given point with the given slope. a) point (3,-2) with slope of m=5/3 Answer: y-(-2)=5/3x-3 b) point (3,9) with slope m=(-2/7) Answer: y-9=-2/7x-3 Correct?
March 7, 2010

Algebra
Great! Thanks
March 6, 2010

Algebra
1. Write the equation of the line with the given slope and y-intercept a) m=3/8 and b=6 Answer: y=3/8x +6 b) m=-2 and b=11 Answer: y=-2x+11 c) m=0 and b=6 Answer: y=x+6 Correct?
March 6, 2010

Algebra
thanks!
March 6, 2010

Algebra
Thank you bun, but how did you come up with that anser for B
March 6, 2010

Algebra
3. Find the slope of each line with equation as given. a) Y=4 b) X=2 Answers: a) zero b) undefined 4. Graph the following equations: a) 3x-2y=6 answer: (2,0) and (0,-3) b) 5x+3y=6 (need help with this one) Are they correct and would need help with b.
March 6, 2010

Algebra
Thanks you will, just looking for validation and help on the ones i don't unsderstand. Thanks again.
March 6, 2010

Algebra
1. Compute the slope of the line containing each pair of points. a) (3,7) and (4,7) b) (2,7) and (2,9) c) (5,-3) and (1,7) Here is what I got. a) 0 b) undefined c) -10/4 reduced to -5/2 Correct?
March 6, 2010

math
Thanks. I was translating the problem incorrectly. I got the right answer using the formula A=P*B A=15*102 A=15.30 15.30 + 102.00 = 117.30 Thanks.
February 11, 2010

math
Never mind it's not right..just having a brain fart :-)
February 11, 2010

math
errrgg..i meant i figured out #2 i need help with #1. My formula is as instructed. B=a/p (Base=amount/percent) My answer is: B=102.00/0.15 B=6.80 so the regular prices is 102.00+6.80=108.80 Is that correcT?
February 11, 2010

math
I figured out #1 just need help with #1
February 11, 2010

math
I have two questions. I am trying to use the formulas our teacher used but I am still confused. I will discuss it with him tonight but I just wanted to get a different perspective. #1 Amy paid \$102 for a pair New Balance 1122 running shoes during a 15%-off sale. What was the ...
February 11, 2010

math-percent
Is anyone familiar with this formula for figuring out percent? How it would work? p/100 = of/is
February 10, 2010

Algebra
Help with this one: 2/3+4t=6t-2/15
February 6, 2010

Algebra help
thanks this helps quite a bit.
February 3, 2010

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