Homework Statement
this problem was on my finals and i stared at it for 30 mins straight and still didn't figure it out and now it just bothers me that i don't know how to do the first problem on my final exam.
"find the general solution to the dfq"
xy'+xy= 1-y
Homework Equations...
Homework Statement
Find the general solution to the diff equation using undetermined coefficients
y''-2y'-3y = 3te^-1
Homework Equations
The Attempt at a Solution
r^2 - 2r -3 = 0
r = -1, 3
so y = c1 e^-t + c2e^3t + yp
since e^-t already exists as a solution, i have to...
Homework Statement
Find y2 given
t^2y'' + 3ty' + y = 0 y1(t) = 1/t
Homework Equations
The Attempt at a Solution
i found y, y' and y'' and plugged it back in to the Differential equation,
after doing some work, i'm basicly down to
tv''+v' = 0
where y2 = v/t
so u =...
Homework Statement
Solving this differential equation
ty' + 2y = t^2 - t + 1
Homework Equations
Its linear so i set it up in linear form
y' + y(2/t) = t - 1 +1/t
The Attempt at a Solution
the integrating factor (u) = e ^ integral (ydt) = e^ integral (2dt/t)...
Here's the...
Homework Statement
There is a large bed floating in sea with the density of 765 kg/m^3. What fraction of the bed's volume will be under the surface of the water? The density of sea water is 1035 kg/m^3.
Homework Equations
Fb = Density * v * gravity
The Attempt at a Solution
I know...
Homework Statement
A small cube (m=0.450 kg) is at a height of 393 cm up a frictionless track which has a loop of radius, R = 58.95 cm at the bottom. The cube starts from rest and slides freely down the ramp and around the loop. Find the speed of the block when it is at the top of the loop...
Homework Statement
An object weighing 341 N in air is immersed in water after being tied to a string connected to a force scale. The scale now reads 307 N. Calculate the density of the object.
Homework Equations
Fb=(density of the surrounding liquid)(V)(g)
The Attempt at a...
Homework Statement
Find the minimum diameter of an l = 17.2 m long steel wire that will stretch no more than 7.38 mm when a mass of 323 kg is hung on the lower end. (Hint: The Young's modulus of steel is 200.0 GPa.)
Homework Equations
Youngs = (Force / Area) / (change L / L)...
Homework Statement
A mass M is suspended from a spring and oscillates with a period of 0.880 s. Each complete oscillation results in an amplitude reduction of a factor of 0.96 due to a small velocity dependent frictional effect. Calculate the time it takes for the total energy of the...
Homework Statement
On a roller coaster ride the total mass of the cart - with passengers included - is 280 kg. Peak K is at 46.0 m above the ground, peak L is at 21.5 m. The speed of the cart at K is 17.1 m/s, at L it is 12.8 m/s. How much energy is lost due to friction between the two peaks...
Homework Statement
A small cube (m=0.450 kg) is at a height of 393 cm up a frictionless track which has a loop of radius, R = 58.95 cm at the bottom. The cube starts from rest and slides freely down the ramp and around the loop. Find the speed of the block when it is at the top of the loop...
Homework Statement
A solid sphere of uniform density (weight = 3.2 lbs starts from rest and rolls down a ramp (H = 1.57 m, q = 18.3°.)
Find the speed of the sphere's CM when it reaches the bottom of the ramp.
haha sorry bout that....
Homework Equations
see below
The Attempt at...
Homework Statement
Four blocks are on a horizontal surface. The blocks are connected by thin strings with tensions Tx, Ty, Tz. The masses of the blocks are A=22.0 kg, B=21.0 kg, C=17.0 kg, D=27.0 kg. Two forces, F1=83.0N and F2=50.0N act on the masses as shown. Assume that the friction...
Homework Statement
A block is at rest on a plank whose angle can be varied. The angle is gradually increased from 0 deg. At 26.5°, the block starts to slide down the incline, traveling 3.10 m down the incline in 2.00 s. Calculate the kinetic coefficent of friction between the block and the...
Homework Statement
A 1.65 kg mass is suspended from a string which is pulled upward. The mass accelerates upwards with an acceleration of 3.10 m/s^2. What is the tension in the string?
Homework Equations
f = ma
The Attempt at a Solution
seems really easy but i can't get the right answer...
Newton's law "trick?" question
Homework Statement
A 40 kg girl and a 50 kg boy are on the surface of a frozen lake, 10 m apart. Using a rope, the girl exerts a horizontal 5.0 N force on the boy, pulling him toward her. Calculate the magnitude of the girl's acceleration.
Homework Equations...
Trajectory, "does it clear a certain height" problem help!
Homework Statement
A place kicker must kick a football from a point 45.5 m from the goal, and the ball must clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 19.0 m/s at an angle of 48.0°...
Homework Statement
Take a loop of wire with a radius of 2.0 cm. A B field is perpendicular to the area enclosed by the wire. If the field is reduced to zero from 0.55 T in 0.25 s, what is the induced emf between the ends of the wire?
Homework Equations
B=Magnetic Field
A=Area
Flux=...
Homework Statement
Take three charged objects and place them on the x-axis. The first charge is + 11 microC, and is placed at +0.85 m. The second charge is -4.6 microC, and is placed at -0.22 m. The third charge is placed at the origin. If the net force on the third charge has a magnitude of...
Homework Statement
Shake a rope so that it makes three "humps" (known more formally as anti-nodes). If you shake the rope up & down 12 times in 9.5 seconds while you and your partner are 2.5 m apart, what is the speed of the wave through the rope?
Homework Equations...
Homework Statement
The density of fresh water is 1000 kg/m3. Normal air pressure (i.e., 1 atm) is 1.013(105) Pa. If someone were beneath 25.0 m of water, what pressure would they experience? Give your answer in Pascals and in atmospheres.
Homework Equations
i guess the (density of...
Homework Statement
Hang a 0.25 kg rock from the end of a spring. If the spring stretches 0.25 m, what is the spring constant?
Homework Equations
i'd assume
F/A=Y(Change in L/Lo)
The Attempt at a Solution
I can do it if there was Area, but there isn't. there's probably another...
Homework Statement
I need one more question answered =D thanks
A man is standing on a spinning turntable with a weight in each hand. His moment of inertia with arms outstretched is 16Nm. WIth his arms by his sdie his moment of Inertia is 6.4Nm. With arms outstreched he makes one rotation in...
Homework Statement
What angular velocity would cause a centripetal acceleration of 3 g's if the radius were 2.5 m?
i have a test 2moro on this stuff... yea i need to know =D thx
Homework Equations
i guess m(v^2)/r or mW^2r
The Attempt at a Solution
no idea. srry :confused:
Homework Statement
Hi, this is my first time on this forum, so don't flame me for not doing things right. I'm a junior in high school and currently taking AP physics, this problem in my hwk has been bothering me for a while. I've never recieved the answer to this question and i jsut need to...
Hi, this is my first time on this forum, so don't flame me for not doing things right. I'm a junior in high school and currently taking AP physics, this problem in my hwk has been bothering me for a while. I've never recieved the answer to this question and i jsut need to know if i did this...