Homework Statement
write two independent equations using kirchoff rule to describe the circuit.
Homework Equations
V=IR
Emf = IR
The Attempt at a Solution
The answer is
emf2 -I1R3-I2R2-I1R1 = 0
(ok i have questions here: why is it I1R1? shouldnt it be I4R1?)
and...
Homework Statement
A circuit with one 5V and 3 resistors in parallel. What is the voltage across one of the resistors?
Homework Equations
V=IR
The Attempt at a Solution
5/3 V??
or should i put
R1 = 5V/I -R2-R3 V
how do we get voltage across one of the resistors without...
wats the R for V_a?
wats the R for V_p?
are they different?
i think the R for V_a is ((s/2)^2 + d^2 ) )^ (1/2)
but for V_p....
is it just s/2?
if thats true i dont think i will get 0 for \DeltaV = V_p - V_A
Homework Statement
We know the magnitude of the electric field at a location on the x axis and at a location on the y axis, if we are far from the dipole.
(a) Find \DeltaV= V_p - V_a along a line perpendicular to the axis of a dipole. Do it two ways: from superposition of V due to the two...
Homework Statement
He2+
2 protons and 2 neutrons
Homework Equations
E = Kq/r^2
The Attempt at a Solution
to get q
do square the charges of the proton? or do I multipy it by 2
im having trouble with part c
it says its a yoyo
and the string is wrapped around the axis
and the radius casing >>>> radius of axis
but i didnt that would matter because the string is wrapped around the axis
but then the problem says
I >>>> m(r_axis)^2
and then i go ...
ok
for vertical a in the -y direction
a_y = ( -gmr^2 ) / (I + mr^2)
i dont see T in the equation
so but it has to affect a_y
but i do see I
and if i make that equal to 0
i get
a_y = -g
WOWOW
thats amazing
thanks!
ur right
i contradicted myself
anyway
my logic tells me
if t = 0, there is no tension and the object should just fall
and so -y direction its a=g (linear)
but the equations tells me otherwise
that when t = 0
a = 0
(as seen in picture)
that does not make sense to me...
im having trouble with part B
i think when t=0, a = 0 because
if I goes to zero, t no longer does work on rotation but does work on linear acceleration
but if the tension goes to 0 then the object will continue to spin but simply fall in the -y direction due to gravity
right?
Unwinding Cylinder--Dynamics
Homework Statement
A cylinder with a moment of inertia I (about its axis of symmetry), mass m, and radius r has a massless string wrapped around it which is tied to the ceiling (Intro 1 figure) .
At time t=0 the cylinder is released from rest at height h...
what are you trying to say?
the initial energy = 0
becuz the objects are at rest and spring is at its natural lenght
so therefore
the final energy is K + U which is equal to Wd
that?
and so
.5m(v_1f)^2+.5m(v_2f)^2-.5kx^2 = (100N/m)(.08m)
KE m1 KE m2...
Homework Statement
m_1, v_1f
m_2, v_2f
m_2 = m_1 = m
Homework Equations
KE = .5mv^2
W = F*d
spring: F= -kx
pot energy = PE = -.5kx^2
The Attempt at a Solution
A) K + U = .5m(v_1f)^2 + .5m(v_2f)^2 - .5kx^2
.5(.1kg)(v_1f)^2 + .5(.1kg)(v_2f)^2 -.5(100N/m)(.02m)^2
B) ...
Homework Statement
The Earth can be approximated as a sphere of uniform density, rotating on its axis once a day. The mass of the Earth is 5.97×10^24 kg, the radius of the Earth is 6.38×10^6 m, and the period of rotation for the Earth is 24.0 hrs.
What is the moment of inertia of the...