Homework Statement
A supersonic plane flies at Mach 3 at an altitude of 20,000 m. A person on the ground sees the plane directly overhead. How much time passes the before she hears the sonic boom?
Homework Equations
f=fo(v+-vo/v-+vs)
The Attempt at a Solution
I don't really know...
Homework Statement
Humphrey the Singing Whale and his mate Matilda swim toward each other, with Matilda swimming twice as fast as Humphrey. When Humphrey sings a note of a frequency 299 Hz. Maltida hears a frequency of 302 Hz. How fast is Humphrey swimming? (The speed of sound i sea water is...
Never mind what i was doing was wrong i was subtracting .18-90 and the sine of that time 0.2m is .199m
but what hypnosam is doing seems right
I did y= 0.2sin[0.18(0)+90(0)-pi/4] but i just don't know how he got 0.707 when inmy calculator i get 0.013 for sin(-pi/4) wth.
Homework Statement
y=0.2msin[(0.18rad/m)x+(90 rad/s)t - pi/4]
What is the displacement at position x=0 and t=0?
Homework Equations
y(x,t)=Asin(kx-wt+phi)
The Attempt at a Solution
y=0.2m[0.18-90]=-0.199m
the answer is -.141 m help?
Homework Statement
Calculate the work done by a gas as it slowly expands from point A to point B on the pV diagram shown.
Homework Equations
Work=PΔV
The Attempt at a Solution
I calculatate the area under the curve and added both of the areas and I came up with 8*10^11 J and the...
Homework Statement
10g of ice at 0 degrees Celcius is combined with 2 g of steam at 100 degrees Celcius. Find the final temperature of the resulting water.
Homework Equations
mc(Tf- Ti)
m(Lf) or m (Li)
The Attempt at a Solution
ΔQice=mLice+mcwaterTf...
OK this is what I'm doing
1. cool to freezing point
q=(.250kg)(4186J/kgK)(273K-283K)=-1.046*10^4J
2.Freeze
MLf=(.250)(3.33*10^5)=8.32*10^4 J
3.Cool to final temp
Q= (.250kg)(2090j/kgK)(-283K-273K)=-2.90510*10^5
so when i sum up Q1+mLf+Q2= -2.177*10^5 J
Like seriously what am i doing wrong?
Homework Statement
How much heat is released when 250 g of water at 10 degrees celcius freezes into ice and cools to -10 degrees celcius?
Homework Equations
Q=mcΔt
The Attempt at a Solution
q= (250g)(4186)(283-273)=1.046*10^4 J
than q=(250g)(2090)(263-283)=-1.045*10^4 J
when i subtract...
Homework Statement
The water from a pipe flows into a tank of volume 180 m3. If the tank is initially empty, how long will it take to fill the tank?
Homework Equations
Q=vA
v1=12m/s
v2=22m/s
A2=0.180982 m2
A1=0.3318 m2
The Attempt at a Solution
This question is the third...
Homework Statement
a) A sailor uses a rope to lower an iron ball of radius 30 cm a to a depth of 80 m below the surface of the ocean. What is the pressure (in atm) at that depth? b) Find the tension in the rope in the previous problem. The density of iron is 7.86 *103 Kg/m3.
Homework...
Homework Statement
A Christmas tree ball hangs from a hook in the ceiling. If the radius of the ball is 8 cm, find the period of the ball's oscillation as it swings on the hook.
Homework Equations
T=2pi*√L/g
The Attempt at a Solution
I tried pluggin the number and i'm way off...
Got it!!!! yeah i really didn't have to use any angular velocities. The hard part was assuming that the mass is 1 kg. because it only mentions mass and they don;t mention anything else so i tried 1 kg just for curiosity.
I used T=2pi*sqrt(m/k) i knew that k=F/deltay so (1kg)(9.8)/0.03m=326.7...
Homework Statement
a)When a mass is attached to the end of a vertical spring, the spring is stretched down 3 cm. If the mass is pulled down a bit farther and then released, what is the period of oscillation of the mass on the spring? b) if the mass moves through its equilibrium position at 50...
The thing is that i don't think this problem should be base with integrals, it has to be an easier way, sqrt(3.27*106)(12.8*106+6.37*106) and still i don't get the right answer.
I mean there has to be another factor that I am not taking into account. I know this problem does not need integrals.
yes a=Gm/r^2 that's how i got the acceleration of the white dwarf
The radius is equal of the earth's radius which is 6.37*10^2 and the mass was the same the sun which was 1.99*10^30. However, I still don't understand your question.
Homework Statement
An apple is dropped from a height of 12.8*10^6 m above the surface of the white dwarf. With what speed does the apple strike the surface of the white dwarf?
M of white dwarf= 1.99*10^30
gravity of white dwarf= 3.29*10^6
Homework Equations
Vf^2=Vi^2+2a(deltaX)...
LOL no. So the KEf is 0 after all? I thought it was 0 because after the collision they both have no kinetic energy because they have no velocity. They both come to a stop. Don't know if my reason is indeed correct.