Homework Statement
The sound level in a noisy classroom is 101 dB. How much energy in J is transmitted to the outside through an open window of height 2 m and width 2.75 m, if the class is 40 minutes long?. What is the decibel rating 1 km from the classroom, assuming sound is distributed...
Well according to my knowledge, in rotational kinematics, acceleration is perpendicular to the velocity. Therefore it should be centripedal acceleration.
Homework Statement
The A-string (440Hz) on a piano is 38.9cm long and is clamped tightly at both ends. If the string is under 667-N tension, what is its mass?Homework Equations
\lambda = vT
\mu = mass/length
v = \sqrt{F/\mu}The Attempt at a Solution
I don't really know which equations to useI...
Homework Statement
Benzene (C6H6) is a liquid which burns in air to form liquid water and carbon dioxide. Calculate the heat released by burning one gram of benzene.
\DeltaHof, kJ/mol
carbon dioxide (g) = -393.5
water (l) = -285.8
benzene (l) = 49.04
Homework Equations
2C6H6 (l) +...
Homework Statement
I'm confused about when to use which formula.
I thought for inelastic collisions,
for example, when a bullet is shot into a block,
I should use
(mbullet)(vinitial) = (mbullet + mblock)(vfinal)
but it turns out that I must use
why do i have to use this one...
Start with:
Wnc = \DeltaK + \DeltaU
for part 1, you are looking for Vf
this gives you...
-(0.21)(37.8)(7.96) = (1/2)(4.5)(Vf2) - (4.5)(9.8)(4.1)
turns out that Vf is 7.23m/s .. tell me if it's right.
for part 2, you are looking for [B]s, the distance
you use the same: Wnc =...
This involves energy right? So kinetic and potential energies have to be considered.
(I just finished learning this, so I might be wrong) :)
Looks like a webwork problem to me... :D
Homework Statement
I don't know when the work of a spring is negative, and when it's positive... When is the work of a spring negative and when is it positive?
Homework Equations
Wsp= -(1/2)(k)(xf2-xi2)
The Attempt at a Solution
I can get Wsp to be positive when the spring is...
Homework Statement
Why does the chemical reactivity increase as we go down in a group?
Homework Equations
none
The Attempt at a Solution
I know it has to do with the atomic radius... but I'm not sure :P
I'm not really interested in calculus, chem, or physics. I mean, I'm doing good in the subjects...
but I don't really like any of them. How can I choose a career in the science field if I don't like any of them? I'm soo bored and pressured right now with theses subjects... and even a little bit...
There's a lot of memorization involved. BUT, there's a lot of logic to it too. So spend time really understanding, and you'll do fine. :) i just failed a chem quiz, but that's 'cause i didn't study and didn't try understanding. i don't like memorizing stuff either... and i need to spend a lot of...