trace
Newest questions and responses by trace
Physics
You hear the sonic boom of a highspeed jet plane exactly 3.10 s after it passes directly overhead in level flight. At the time you hear the boom, you see the plane at an angle of 22.0 o above the horizon. Assume that the speed of sound at the altitude of
asked on December 3, 2017 
Physics
A car traveling 35.0 m/s overtakes another car going only 22.0 m/s. When the faster car is still behind the slower one, it sounds a horn of frequency 1500.0Hz. What is the frequency heard by the driver of the slower car? What is the altitude of the plane?
asked on December 3, 2017 
Physics
A car traveling 35.0 m/s overtakes another car going only 22.0 m/s. When the faster car is still behind the slower one, it sounds a horn of frequency 1500.0Hz. What is the frequency heard by the driver of the slower car?
asked on December 3, 2017 
Physics
A harmonic wave moving in the positive x direction has an amplitude of 4.4 cm, a speed of 41.0 cm/s, and a wavelength of 45.0 cm. Assume that the displacement is zero at x = 0 and t = 0. Calculate the displacement (in cm) due to the wave at x = 0.0 cm, t =
asked on December 3, 2017 
Physics
A harmonic wave moving in the positive x direction has an amplitude of 4.4 cm, a speed of 41.0 cm/s, and a wavelength of 45.0 cm. Assume that the displacement is zero at x = 0 and t = 0. Calculate the displacement (in cm) due to the wave at x = 0.0 cm, t =
asked on November 30, 2017 
Busn math
What is the whole number or simplified answer to 3/35 divided by 9/7
asked on July 18, 2016 
Math polynomial functions
State the number of complex roots of each equation then find the roots. I cant figure out these two! 1. 3x  5 =0 2. c^2 + 2c + 1 = 0
asked on December 11, 2011 
pre algebra
In a survery, students were asked whether they play basketball or tennis. Of 34 students, 24 play basketball and 13 students play tennis.4 students play neither. How many students play both sports? Is it 7 students?
asked on April 24, 2011 
pre algebra
In a survery, students were asked whether they play basketball or tennis. Of 34 students, 24 play basketball and 13 students play tennis.4 students play neither. How many students play both sports? Is it 7 students?
asked on April 23, 2011 
physicstelescope
The Hubble Space Telescope (HST) can resolve objects that have a small angular separation because there is no atmospheric distortion of the light. (i.e. The HST has excellent resolving power.) Its 2.4mdiameter primary mirror can collect light from
asked on March 23, 2011 
physics, error calculation repost
I need to derive an error equation for Bohr's model to use in my physics lab this week. I am really bad at calculus, so if anyone can help me that would be really great. the equation is (1/lambda)=R[(1/n^2final)(1/n^2initial)] I've never had to derive
asked on March 8, 2011 
Physics, error derivation
I need to derive an error equation for Bohr's model to use in my physics lab this week. I am really bad at calculus, so if anyone can help me that would be really great. the equation is (1/lambda)=R[(1/n^2final)(1/n^2initial)] I've never had to derive
asked on March 8, 2011 
physics
A child swinging on a swing set hears the sound of a whistle that is being blown directly in front of her. At the bottom of her swing when she is moving toward the whistle, she hears the higher pitch, and at the bottom of her swing, when she is moving away
asked on March 3, 2011 
physics
The length of the auditory canal in humans averages about 2.5 cm. What is the second lowest standing wave frequency for a pipe of this length open at one end? Use 345 m/s for the speed of sound. I know that 4L=lambda, so lambda= 10cm. I know that
asked on March 3, 2011 
physics graphing help please
(a) Write the equation for a transverse sinusoidal wave with a maximum amplitude of 2.5 cm and an angular frequency of 2.9 rad/s that is moving along the positive xdirection with a wave speed that is 5.00 times as fast as the maximum speed of a point on
asked on February 9, 2011 
physics, I'm stuck
It takes a flea 1.0x10â€“3 s to reach a peak speed of 0.74 m/s. (a) If the mass of the flea is 0.45x10â€“6 kg, what is the average power required? (b) Insect muscle has a maximum output of 60 W/kg. If 20% of the fleaâ€™s weight is muscle,
asked on February 2, 2011 
Health
why isnt there any correlation between the monthly rainfall and Ross River Virus?
asked on January 30, 2011 
physics, I'm stuck
In an aortic aneurysm, a bulge forms where the walls of the aorta are weakened. If blood flowing through the aorta (radius 1.0 cm) enters an aneurysm with a radius of 2.5 cm, how much on average is the blood pressure higher inside the aneurysm than the
asked on January 27, 2011 
ART
i need to describe my public identity by drawing. can you please give me some ideas? please? i want to know your public identity so that i understand mine. i don't know anything ... but is it ok if i say, i catch the bus to school everyday and i like
asked on January 27, 2011 
physics
specific gravity: Suppose the hydrometer has a cylindrical stem of crosssectional area 0.400 cm2. The total volume of the bulb and stem is 8.8 cm3 and the mass of the hydrometer is 4.8 gm. (c) What is the lowest specific gravity that can be measured with
asked on January 25, 2011 
physicstorque
A person is doing leg lifts with 3.0kg ankle weights. She is sitting in a chair with her legs bent at a right angle initially. The quadriceps muscles are attached to the patella via a tendon; the patella is connected to the tibia by the patellar tendon,
asked on January 19, 2011 
Physicsmoment of inertia PLEASE HELP
this is the question : A CD has a diameter of 12.0 cm and a mass of 15.8 g. The motor in a CD player causes the disk, initially at rest, to spin. When in operation, the CD spins in such a way that the laser scans the tracks at a constant tangential
asked on January 19, 2011 
physics
The deepest place in the ocean is the Marianas Trench in the western Pacific Ocean, which is over 11.0 km deep. On January 23, 1960, the research sub Trieste went to a depth of 10.915 km, nearly to the bottom of the trench. This still is the deepest dive
asked on January 18, 2011 
physics
A CD has a diameter of 12.0 cm and a mass of 15.8 g. The motor in a CD player causes the disk, initially at rest, to spin. When in operation, the CD spins in such a way that the laser scans the tracks at a constant tangential velocity of 1.20 m/s. The
asked on January 18, 2011 
PHYSICS
A beam of electrons is moving in a horizontal circle in a uniform magnetic field that is directed downward. The speed of the electrons is 1.0*10^7 m/s and the magnitude of themagnetic field is 1.0*10^3 T. As seen from above, are the electrons moving
asked on November 29, 2010 
PHYSICS
Find the force on a proton, with kinetic energy 10keV, that is moving perpendicular to a magnetic field of magnitude 2.0kG. I know I need to find the velocity, and then use F=qvBsinTHETA, but I'm so bad at equating different parts of formulas. Can anyone
asked on November 29, 2010 
physics
A ball player wishes to determine her pitching speed by throwing a ball horizontally from an elevation of 3.0 m above the ground. She sees the ball land 15 m down the range. What is the speed of the ball as it leaves her hand?
asked on November 28, 2010 
physics
A mass of 1.00kg is dropped from a height of 80cm onto a spring, of unstretched length of 20.0cm, which is resting on the floor. It comes to rest, momentarily, at a height of 10.0cm from the floor. If we can ignore friction, find the spring constant of the
asked on November 24, 2010 
physics
A uniform magnetic field points North; its magnitude is 1.5 T. A proton with kinetic energy 8.0x10–13 J (5.0 MeV) is moving vertically downward in this field. What is the magnetic force acting on it? I have no idea where to start with this question, can
asked on November 23, 2010 
physics
this question is about resistors in parallel. If i have a circuit, and it starts at point A with one resistor, then splits to flow to two resistors, and one of those two splits agin, to two more, then they all join again at the end at point B, what
asked on November 23, 2010 
physics
During a “brownout,” which occurs when the power companies cannot keep up with high demand, the voltage of the household circuits drops below its normal 120 V. (a) If the voltage drops to 108 V, what would be the power consumed by a “100 W”
asked on November 23, 2010 
physics
A 2.00 kg block, on a horizontal surface with coefficient of static friction 0.900, is pushed by a force that is directed down at an angle of 30.0 degrees to the horizontal. Find the minimum magnitude of the force needed to get the block to start moving.
asked on November 19, 2010 
Physics
A copper wire has a resistance of 24 Ω at 20°C. An aluminum wire has three times the length and twice the radius of the copper wire. The resistivity of copper is 0.6 times that of aluminum. Both Al and Cu have temperature coefficients of resistivity of
asked on November 17, 2010 
English
i need an urgen help with my eulogy can someone please help me, please. i cant do some parts properly,and am not sure of some parts. so really need help. This is a hard moment. It’s the moment we must say farewell to the to the brave young man, Callum
asked on November 16, 2010 
health Ed
please please pleeeeeeeeeeeeeeeeeeeeeeeaaaaaase help! What are the societal influences (economic, education and government policy) that can contribute to a supportive family environment? (Focus on families with adolescents)
asked on October 28, 2010 
calculus
assume the halflife of the substance is 31 days and the initial amount is 183.9 grams. (a) Fill in the right hand side of the following equation which expresses the amount A of the substance as a function of time t (the coefficient of t in the exponent
asked on September 16, 2010 
Claculus
find the equation of the tangent line to y^3xy=6 at the point (7,2)
asked on June 21, 2010 
Caluclus
use implicit differentiation to find dy/dx xlny=y^3=lnx
asked on June 21, 2010 
chems
how many grams of CO will contain 4.10 x 10^12 molecules
asked on November 15, 2009 
chemistry
how many grams of Sb2S3 will contain 4.80 moles of S
asked on November 14, 2009 
chemistry
what is the mass of one mole of carbon dioxide?
asked on November 14, 2009 
chemistry
how many grams of phosphorus are there in 160 g of P4O10
asked on November 10, 2009 
chemistry
how many moles of CH4 will contain 4.31 x 10^23 molecules
asked on November 9, 2009

physicstelescope
I tried to get help from a friend, but her email just said to use tan theta = x/D. I'm not sure why she said to use tan theta, and when I do that> tan 0.00001165*2.4m=x I get x= 0.000000487 which is obviously not right.
posted on March 24, 2011 
physicstelescope
My prof says that the answer should be of magnitude 10^19. I'm not sure what he's doing differently. Is there another way to solve this?
posted on March 24, 2011 
physics, error calculation repost
sorry, edit, that would be (deltaM/M + deltaT/T)N
posted on March 8, 2011 
physics, error calculation repost
Hi Bob, I have to derive the error in the wavelength. I only know how to derive error equations from multiplication or addition/subtraction. For example, if I needed to derive an arror equation for N=MT it would be deltaN=(deltaM+deltaT)N So how do I do it
posted on March 8, 2011 
physics
I guess I gave up too soon!
posted on March 3, 2011 
physics
okay, so I set it up as a ratio: [(1v child)/v]*freq sound OVER [(1+v child)/v]*freq sound ALL THAT =1.05 So I have 1.05=[(1v child)/343]/[(1+v child)/343] But I can't figure out how to manipulate this equation. I keep getting the v child as 341 m/s, and
posted on March 3, 2011 
physics
I used the eq. f=n(v/4L). Where n=3 bc that is the second lowest frequency in a tube with one end open.
posted on March 3, 2011 
physics, I'm stuck
thank you so much! Have a good night
posted on January 28, 2011 
physics, I'm stuck
thanks! but when i checked the conversion online, 750 dyne converts to 75 Pa, not 75kPa, which conversion is correct? Is there a reason you have a different conversion, that I'm not seeing?
posted on January 28, 2011 
physics, I'm stuck
thanks!
posted on January 28, 2011 
physics
Thanks!
posted on January 27, 2011 
physics
yes you were right, I only showed 5 and the question had six. I figured it out finally. What I didn't understand was that I had to find the resistance of the first set of parallels and then ADD that to the one beside it in series, then take the parallel of
posted on November 24, 2010 
physics
I think the delta in front of voltage is just there because measured voltage is the potential difference, ie. delta
posted on November 24, 2010 
physics
oh I think I have found the answer! Sorry
posted on November 19, 2010 
Physics
how did you get this?
posted on October 10, 2010