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...
Homework Statement
Suppose you are standing on the center of a merry-go-round that is at rest. You are holding a spinning bicycle wheel over your head so that its rotation axis is pointing upward. The wheel is rotating counterclockwise when observed from above.
For this problem, neglect...
Homework Statement
There are two balls travelling and they collide. How do there momentum change.
What is the impulse done to ball B by ball A.
Homework Equations
delta momentum = 0
impulse = ?
The Attempt at a Solution
the first part
i think its C
becuz A is moving up...
Homework Statement
its asking me if if it is easier to use the mass units
Homework Equations
PART A
The Attempt at a Solution
its it easier to to use numbers given becuz
when add the numbers
(3.9) / ( 1 - 16 / (16+133) ) = 4.3 = kinetic energy needed for O ionize C
4.3 > 4...
ok the next questions asks about about momentum
im thinking
centripital acceleration cannot be zero becuz
is it zero? i dont think so becuz its traveling on a circular path prior to leaving the globe
normal force must be zero becuz nothing is pushing up
the net acceleration is...
Homework Statement
There are two balls with masses m_a and m_b connected by a string. m_b is moving at a velocity v upwards (perpendicular to the string) and it asks for the Tension (T) in the string.
Homework Equations
a=(v^2)/R
delta Energy of system = 0
T = m((u^2)/r)
u is...
and so it is a and c
becuz
once the block leaves the globe
nothing is pushing the box up (but friction) and nothing is slowing the box down in the horizontal direction (but friction)
and so the only force is the earth?
right?
Homework Statement
there is a block sliding down a big globe in Italy.
Homework Equations
uhh
The Attempt at a Solution
does the globe have its own gravity?
i'm thinking its A and C.
im solving for Vo
the object is launched from above the atmosphere
im given the distance between object and mars (R_m)
and I'm given the weight of mars (m)
and I'm given Vf of the object
so what I did (but I did not get a good answer)
was use
F=Gm1m2/r^2
m1 = object
m2 =...
Homework Statement
The Radius of Mars is R_m
its mass is m
The radius of Mars (from the center to just above the atmosphere) is R_m and its mass is m. An object is launched from just above the atmosphere of mars.
A) what is the object's initial velocity if its final velocity is V_f
Homework...
ok
now both the blocks have the same speed
and now have the same V
ok...
and its asking for distance
so i have to find out how far each box is pushed
and
work of larger box =
W_L= F*D_L
W_S=F*D_S
KE_L = .5(4M)(v)^2
KE_S = .5(M)(v)^2
and since W=chainge in KE (KE_initial...
ok for part b it is asking how fast the lighter block is moving when compared to the big block.
im thinking
the F*D is the same
and KE is .5mv^2
and so
.5(4m)(v_L)^2 = .5m(v_S)^2
the m and .5 cancel out
so i have
4(V_L)^2=(V_S)^2
SQRT BOTH SIDE
and then
V_S = 2V_L
so therefore
the...
ok i figured out the first part
how do i figure out part B?
I kno the power is proportional to v^3
and so if i increase the power by 10%
i should get
??
if Pi = -(vi^3)AC_d
then 1.1Pi=-(vf^3)AC_d
Pi = (-(vf^3)AC_d ) / 1.1
(vf^3) = 1.1(vi^3)
then what?
Homework Statement
the force is given as F
the distance pushed is given as D
Homework Equations
W= F*d
F=ma
KE = 1/2 mv^2
The Attempt at a Solution
the blocks have the same kinetic energy