Homework Statement
We sink ball with density 1450 kg/m^3 in some liquid with density 1400 kg/m^3
a) What's acceleration in moment we drop the ball?
b) With what constant speed will the ball sink in balace? Assuming that the drag force is linear. Radius of ball is 3mm and viscosity of...
Problem is i don't know if M is constant, but guessing from what you wrote its not, so my equations are all wrong.
So... Wrot=2*ω^(2)/J
ω^2=Wrot*2/J
edited: A=Wk2-Wk1 --> A=Wrot
:smile:
ω=sqrt((A*2*η)/J)=8,366 rad/s
Thanks :)
First of all I am sorry for my awful english.
Homework Statement
Electric motor starts turning wheel with a constant power of P=25W and J=3 kg*m^2. With what angular velocity the wheel spins after 7s(from start), if the efficiency is 60%Homework Equations
P=M*ω
M=J*αThe Attempt at a Solution...
I used 3.6*10^-3 km/s^2 for g0 when i calculated, so its (km*km^(3/2))/sqrt(km*s^(-2)*km^2). Then km^(3/2)/km^(3/2)=1, so all it stays is km*s.
Repair me if I am wrong :)
Ok i made some changes, so now
t= (2*r(R+h)^(3/2))/(sqrt(g0*R^2))
r=R+h
R=3400km
h=150km
g0=3,7 m/s^2... assuming i should of know g0 from mars.
I calculated and it came out t=7261412,315 km/s...:confused:
g0=9,81m/s^2
hmm … don't you need to know either the mass of Mars, or the gravitational acceleration (g) at the surface?
i could calculate g at surface using g=g0*R^(2)/(R+h)^2, but then again i have no idea what to use it for
.. nevermind g0 is different on Mars then on Earth so..
Homework Statement
On high 150km above the surface of Mars, there is satelite That is ciculating arround Mars. What's his bypass time? Radius of Mars is 3400km.
Homework Equations
The Attempt at a Solution
I found equation like this :
t= (2*r(R+h)^(3/2))/(sqrt(g0*R^2))
R=r+h
r=3400km
h=150km...