# Search results

1. ### Percentage Weight Question

Homework Statement You have a 20% w/v stock solution of a sugar of molecular weight 160 Daltons. How much of this stock solution will you need to use to... a. prepare 10 ml of solution at 350 mg sugar per ml. b. 7 ml of solution containing 15 micromoles of sugar Homework Equations...
2. ### Dilution Question

Homework Statement Addition of 2uL of 50mM NaCl to a 30 uL reaction gives a final NaCl concentration of ______ M. Homework Equations The Attempt at a Solution so because you add 2uL to 30uL, the dilution is (2 / 2+30) = 1/16 Then I multiplied the dilution with the concentration...
3. ### Dilution Question

Hello all, I just want to confirm that I am on the right track for a certain question regarding dilution and concentration Q: Addition of 2uL of 50mM NaCl to a 30 uL reaction gives a final NaCl concentration of ______ M. Attempt: so because you add 2uL to 30uL, the dilution is (2 / 2+30)...

help any 1 ?
5. ### What is the lowest-frequency standing wave

Homework Statement A 22-cm-long, 1.0-mm-diameter copper wire is joined smoothly to a 60-cm-long, 1.0-mm-diameter aluminum wire. The resulting wire is stretched with 20 N of tension between fixed supports 82 cm apart. The densities of copper and aluminum are 8920kg/m^3 and , 2700 kg/m^3...
6. ### Tension of String/ Mass question

Homework Statement The figure shows two masses hanging from a steel wire. The mass of the wire is 60.0 g. A wave pulse travels along the wire from point 1 to point 2 in 24.0 ms. What is mass m? Homework Equations v = sqrt(Ts/mu) The Attempt at a Solution T=mu*v^2 t = 0.024s d = 4m v =...
7. ### Doppler's Effect

omgosh ... i got the equation wrong...lol it's fo /(1 +/- vs/v) my bad. thanks
8. ### Doppler's Effect

Homework Statement A physics professor demonstrates the Doppler effect by tying a 600 Hz sound generator to a 1.0-m-long rope and whirling it around her head in a horizontal circle at 100 rpm. Homework Equations f =fo(1/ (V +/- Vsource/V)) The Attempt at a Solution T =...
9. ### VSEPR Question

Homework Statement Give the formula of a fluoride molecule that: is octahedral in shape is trigonal bypyramidal in shape is T-shaped ...etc The Attempt at a Solution Ok, I'm not really actually looking for an answer, because I already know the answers are SF6, PF5, and ClF3. And I have...
10. ### Phase Constant graph help

thanks a lot learningphysics and house md
11. ### Phase Constant graph help

all the solution is there, but i just don't understand the answer to part B. for part B, why is the sign negative?
12. ### Wave Speed As a Function of Tension

now i get it! thanks so much! the ansr i got was a=-1/2 and b=1/2, which is in accordance with v = sqrt(T/mu)
13. ### Wave Speed As a Function of Tension

by using exponents on both side, do u mean to raise m/s to the power of (a+b)(b-a)(-2b)??
14. ### Wave Speed As a Function of Tension

sry forgot to say mu is mass per unit length of the wire
15. ### Wave Speed As a Function of Tension

Homework Statement This is a question from my lab manual v=Cmu^aT^b (4.3) Use dimensional analysis of equation (4.3) to determine the exponents a and b. Homework Equations i know that the proper equation is v=sqrt(T/mu) The Attempt at a Solution I tried dimensional to get some...
16. ### Standard error

thank you very much!
17. ### Standard error

[SOLVED] Standard error Homework Statement A student determined the following values for the wave speed; calculate the average value of the wave speed and its standard error 50.8, 50.6, 51.8, 52.0, 50.9, 51.6, 51.3, 51.5 Homework Equations avg wave speed = 51.3 The Attempt at a...
18. ### Fluid cylindrical bucket Question

really? ? any idea what i converted wrong? did you get 0.01718m/s and 0.01530m/s for velocities? ... hm
19. ### Fluid cylindrical bucket Question

A cylindrical bucket, open at the top has height 27.0 cm and diameter 13.0 cm. A circular hole with a cross-sectional area 1.49 cm^2 is cut in the center of the bottom of the bucket. Water flows into the bucket from a tube above it at the rate of 2.28×10−4 m^3/s my work let 1 denote the top...
20. ### Function Question

I see! Thanks a lot!
21. ### Function Question

Let f be the function that takes the value of 1 on all rational numbers, and 0 on all irrational numbers. At what points is f continuous? Does anyone know how to do this?? I mean, there are just so many points to point out...such as square root of 2 and 10, and the list is endless...
22. ### Error Analysis Question

given that a=(6.0+/-0.1) and b=(17.5+/-0.3) what is 2a^2 + b^2 i'm having so much trouble with this i think we first go (6.0+/-0.1)^2 then times it by 2, and add (17.5+/-0.3)^2...i tried this but couldn't get the right answer...what am i doing wrong? ...ANY help would be greatly...
23. ### Doppler effect of a motorcycle

a motorcycle starts from rest and accelerates along a straight line at 2.81m/s^2. the speed of sound is 343 m/s. a siren at the starting point remains stationary. how far has the motorcycle gone when the drive hears the frequency of the siren at 90.0% of the value it has when the motorcycle is...
24. ### Circular Motion Bug Question

hey nvm i got it :)
25. ### Circular Motion Bug Question

If the coefficient of friction between a bug and the turntable is 0.55 and the bug is 25 cm from the centre, how fast (in RPM) does the turntable have to spin to cause the bug to slide off? All I know so far is that the frictional force must be 0 (?) Fc = m4pi^2r/T^2 but this obviously...
26. ### Power of skier Question

In 2.0 minutes, a ski lift raises four skiers at constant speed to a height of 140 m. The average mass of each skier is 65kg. What is the average power provided by the tension in the cable pulling the lift? t= 2.0min(60s/1min) = 120s m = 65kg x 4 = 260kg Wnc = △Ek + △Ep Wnc = Ekf - Eki +...
27. ### Work/Energy Question!

A pendulum bob is on a 2.2m long string. It is released from position A. Find its speed at position B. W = 1/2m(V^2-Vi^2) V = root 2W/m the trouble is I cannot get W because i do not know the displacement. also mass is not given. thank you in advance.
28. ### Momentum and impulse question

A 230N force causes a 4.0kg to accelerate from 5.0m/s North to 3.0m/s east. for how much time does hte force act? t = m(vf-vi) / F i got this but the trouble is vf and vi are in different directions...and since t is not a vector i can't break it down to components. what should i do?
29. ### Physics Gravitational Force Question

thank you very much for your help
30. ### Physics Gravitational Force Question

At a distance H above the surface of a plane, the true weight of a remote probe is one percent less than its true weight on the surface. The radius of the planet is R. Find the ratio H/R. Work: Let Mp be mass of planet and Ms be the mass of space probe (true weight) Ft = GMpM/(r+h)^2...