# COFFEE

Most popular questions and responses by COFFEE-
## Physics - KE/inertia

The rigid body shown in Figure 10-66 (it is a triangle with the upper mass = to M and the bottom two corners/masses equal to 2M. The bottom side length equals .70 cm with point P in the middle of the side and the other two sides equal .55 cm)consists of

*asked on March 27, 2007* -
## physics - waves

Two sinusoidal waves, identical except for phase, travel in the same direction along a string producing a net wave y'(x, t) = (1.5 mm) sin(29x - 4.0t + 0.960 rad), with x in meters and t in seconds. (a) What is the wavelength of the two waves? I found the

*asked on April 15, 2007* -
## physics - SHM

Two sinusoidal waves with identical wavelengths and amplitudes travel in opposite directions along a string with a speed of 11 cm/s. If the time interval between instants when the string is flat is 0.33 s, what is the wavelength of the waves? wavelength =

*asked on April 14, 2007* -
## Physics/Math

At time t1 = 2.00 s, the acceleration of a particle in counterclockwise circular motion is (9.00i + 8.00j) m/s^2. It moves at constant speed. At time t2 = 3.00s (3/4 of a revolution later), it's acceleration is (8.00i - 9.00j) m/s^2. Find the radius of the

*asked on February 18, 2007* -
## Math/Calculus

A spring with a 4 kg mass has natural length 1 m and is maintained stretched to a length of 1.3 m by a force of 24.3 N. If the spring is compressed to a length of 0.8 m and then released with zero velocity, find the position of the mass at any time t. Here

*asked on July 11, 2007* -
## Calculus

The hemispherical tank shown is full of water. Given that water weighs 62.5 lb/ft3, find the work required to pump the water out of the tank. ---------- What is shown is just the tank (a hemisphere) with a radius of 5 ft. ---------- First I calculated the

*asked on June 17, 2007* -
## Calculus

The tank shown is full of water. Given that water weighs 62.5 lb/ft3, find the work required to pump the water out of the tank. The tank shown is a hemisphere with r = 5 ft. The water is to be pumped out at the top. First I solved for ri, ri / (5 - xi) = 5

*asked on June 23, 2007* -
## Calculus

Use Euler's method with step size 0.2 to estimate y(1.4), where y(x) is the solution of the initial-value problem below. Give your answer correct to 4 decimal places. y' = x - xy y(1) = 0 h = 0.2 Since I am at y(1) = 0 and not y(0) = 0 would I just do this

*asked on June 22, 2007* -
## RE: PHYSICS

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at 40.00 m/s relative to

*asked on February 26, 2007* -
## Re: PHYSICS

"Relative" is an important word. Block L of mass mL = 1.90 kg and block R of mass mR = 0.500 kg are held in place with a compressed spring between them. When the blocks are released, the spring sends them sliding across a frictionless floor. (The spring

*asked on February 27, 2007* -
## Re: Physics/Math

Calculate the ratio of the drag force on a passenger jet flying with a speed of 750 km/h at an altitude of 10 km to the drag force on a prop-driven transport flying at one-fifth the speed and half the altitude of the jet. At 10 km the density of air is

*asked on February 10, 2007* -
## Physics

"Relative" is an important word. Block L of mass mL = 1.90 kg and block R of mass mR = 0.500 kg are held in place with a compressed spring between them. When the blocks are released, the spring sends them sliding across a frictionless floor. (The spring

*asked on February 25, 2007* -
## Calculus

The hemispherical tank shown is full of water. Given that water weighs 62.5 lb/ft3, find the work required to pump the water out of the tank. ---------- What is shown is just the tank (a hemisphere) with a radius of 5 ft. ---------- First I calculated the

*asked on June 18, 2007* -
## physics - sound level

The source of a sound wave has a power of 2.50 µW. Assume it is a point source. (a) What is the intensity 6.70 m away? I used I = Power / 4*pi*r^2 and found I to be 4.43x10^-9 W/m^2 (b) What is the sound level at that distance? Sound level = 10 dB*log

*asked on April 21, 2007* -
## calc check: hooke's law

A force of 27N is required to maintain a spring stretched from its natural length of 12cm to a length of 15cm. How much work is done in stretching the spring from 15 to 25cm? and this is what i did.. please check to see if i did it correctly.. thanks :)

*asked on June 29, 2007* -
## physics - doppler effect

Two identical tuning forks can oscillate at 329.6 Hz. A person is located somewhere on the line between them. The speed of sound in the air is 343 m/s. Calculate the beat frequency as measured by this individual under the following conditions. (a) the

*asked on April 21, 2007* -
## Calculus

The tank shown is full of water. Given that water weighs 62.5 lb/ft3, find the work required to pump the water out of the tank. The tank shown is a hemisphere with r = 5 ft. The water is to be pumped out at the top. First I solved for ri, ri / (5 - xi) = 5

*asked on June 22, 2007* -
## Physics - Conservation of Angular Momentum

a man is standing on the center of a platform that is rotating without friction. his arms are outstretched holding a brick in each hand. the rotational inertia of the system consists of the man, bricks, and platform about the central vertical axis of the

*asked on April 8, 2007* -
## Physics - Torque

A particle is acted on by two torques about the origin: T1 has a magnitude of 4.3 N*m and is directed in the positive direction of the x axis, and T2 has a magnitude of 3.2 N*m and is directed in the negative direction of the y axis. What are the magnitude

*asked on March 31, 2007* -
## Re: Physics/Math

At time t1 = 2.00 s, the acceleration of a particle in counterclockwise circular motion is (9.00i + 8.00j) m/s^2. It moves at constant speed. At time t2 = 3.00s (3/4 of a revolution later), it's acceleration is (8.00i - 9.00j) m/s^2. Find the radius of the

*asked on February 18, 2007* -
## RE: PHYSICS

"Relative" is an important word. Block L of mass mL = 1.90 kg and block R of mass mR = 0.500 kg are held in place with a compressed spring between them. When the blocks are released, the spring sends them sliding across a frictionless floor. (The spring

*asked on February 26, 2007* -
## Physics

A vessel at rest at the origin of an xy coordinate system explodes into three pieces. Just after the explosion, one piece, of mass m, moves with velocity (-30 m/s)i and a second piece, also of mass m, moves with velocity (-30 m/s)j. The third piece has

*asked on February 25, 2007* -
## Physics/Math

A stuntman drives a car (without negative lift) over the top of a hill, the cross section of which can be approximated by a circle of radius R = 110 m. What is the greatest speed at which he can drive without the car leaving the road at the top of the

*asked on February 12, 2007* -
## Physics/Math

A certain string can withstand a maximum tension of 43 N without breaking. A child ties a 0.37 kg stone to one end and, holding the other end, whirls the stone in a vertical circle of radius 0.91 m, slowly increasing the speed until the string breaks.

*asked on February 12, 2007* -
## Calculus

A steady wind blows a kite due west. The kite's height above ground from horizontal position x = 0 to x = 80 ft is given by the following. y = 150 - (1/40)(x-50)^2 Find the distance traveled by the kite. y = 150 - (1/40)(x-50)^2 y = 150 -

*asked on June 13, 2007* -
## RE: PHYSICS

A stationary block explodes into two pieces L and R that slide across a frictionless floor and then into regions with friction, where they stop. Piece L, with a mass of 2.0 kg, encounters a coefficient of kinetic friction µL = 0.40 and slides to a stop in

*asked on February 26, 2007* -
## Physics/Math

A certain string can withstand a maximum tension of 43 N without breaking. A child ties a 0.37 kg stone to one end and, holding the other end, whirls the stone in a vertical circle of radius 0.91 m, slowly increasing the speed until the string breaks.

*asked on February 12, 2007* -
## Physics

Two horizontal forces act on a 2.4 kg chopping block that can slide over a frictionless kitchen counter, which lies in an xy plane. One force is F1 = (3.4 N) i + (3.7 N) j. Find the acceleration of the chopping block in unit-vector notation for each of the

*asked on February 3, 2007* -
## Physics/Math

A stuntman drives a car (without negative lift) over the top of a hill, the cross section of which can be approximated by a circle of radius R = 110 m. What is the greatest speed at which he can drive without the car leaving the road at the top of the

*asked on February 12, 2007* -
## Calculus - Second Order Differential Equations

Posted by COFFEE on Monday, July 9, 2007 at 9:10pm. download mp3 free instrumental remix Solve the initial-value problem. y'' + 4y' + 6y = 0 , y(0) = 2 , y'(0) = 4 r^2+4r+6=0, r=(16 +/- Sqrt(4^2-4(1)(6)))/2(1) r=(16 +/- Sqrt(-8)) r=8 +/- Sqrt(2)*i,

*asked on July 10, 2007* -
## Re: PHYSICS

*asked on February 27, 2007* -
## Physics

A worker drags a crate across a factory floor by pulling on a rope tied to the crate. The worker exerts a force of 450 N on the rope, which is inclined at 38° to the horizontal, and the floor exerts a horizontal force of 125 N that opposes the motion.

*asked on February 3, 2007* -
## Physics/Math

A sphere of mass 2.7 x 10^-4 kg is suspended from a cord. A steady horizontal breeze pushes the sphere so that the cord makes a constant angle of 41 degrees with the vertical. Find the magnitude of the push provided by the breeze and Find the tension in

*asked on February 18, 2007* -
## calc: avg value

Find the average value of the function "f(x) = x^2 sqrt(1+x^3)" on the interval [0,2]. and this is what i did.. please check for mistakes. thanks :D f(x) = x^2 sqrt(1+x^3), [0,2] f ave = (1/(b-a))*inegral of a to b for: f(x) dx f ave = (1/(2-0))*integral

*asked on July 2, 2007* -
## Calculus

Find the exact coordinates of the centroid. y = sqrt[x], y = 0, x = 9. -------------- Is this basically 1/4 of an oval/ellipse? If so then the area would be: pi*9*3, correct? So the X coordinate would equal: 1/Area * Integral from 0 to 9 of (x*f(x))*dx

*asked on June 22, 2007* -
## calc: arc length

find the exact length of this curve: y = ( x^3/6 ) + ( 1/2x ) 1/2

*asked on June 11, 2007* -
## Physics - KE/rotation

In Figure 11-32 (which shows a ball at the top of an incline, at the bottom of the incline a loop begins with radius R and Q a point on the loop lined up with the center of the loop), a solid brass ball of mass m and radius r will roll without slipping

*asked on March 25, 2007* -
## Physics

A stationary block explodes into two pieces L and R that slide across a frictionless floor and then into regions with friction, where they stop. Piece L, with a mass of 2.0 kg, encounters a coefficient of kinetic friction µL = 0.40 and slides to a stop in

*asked on February 25, 2007* -
## Calculus - Taylor #2

Find the Taylor series for f(x) centered at the given value of 'a'. (Assume that 'f' has a power series expansion. Do not show that Rn(x)-->0.) f(x) = x3, a = -1 and what i've done so far: f (x) = x^3 f ' (x) = 3x^2 f '' (x) = 6x^1 f ''' (x) = 6x f (-1) =

*asked on July 28, 2007* -
## Calculus - Center of Mass

Find the exact coordinates of the centroid given the curves: y = 1/x, y = 0, x = 1, x = 2. X = 1/Area*Integral from a to b: x*f(x)dx Y = 1/Area*Integral from a to b: [(1/2)*(f(x))^2]dx How do I find the area for this? Once I know that, is this the correct

*asked on June 26, 2007* -
## Physics/Math

In a pickup game of dorm shuffleboard, students crazed by final exams use a broom to propel a calculus book along the dorm hallway. If the 3.6 kg book is pushed from rest through a distance of 0.90 m by the horizontal 22 N force from the broom and then has

*asked on February 10, 2007* -
## Math/Calculus

Please check my work and correct any errors/point out any errors. Thanks. Solve the initial-value problem using the method of undetermined coefficients. y''-4y=e^xcos(x), y(0)=1, y'(0)=2 r^2-4=0, r1=2, r2=-2 yc(x)=c1*e^2x+c2*e^-2x

*asked on July 12, 2007* -
## Math/Calculus

A series circuit contains a resistor with R = 24 ohms, an inductor with L = 2 H, a capacitor with C = 0.005 F, and a generator producing a voltage of E(t) = 12 sin(10t). The initial charge is Q = 0.001 C and the initial current is 0. (a) Find the charge at

*asked on July 12, 2007* -
## Calculus

Please look at my work below: Solve the initial-value problem. y'' + 4y' + 6y = 0 , y(0) = 2 , y'(0) = 4 r^2+4r+6=0, r=(16 +/- Sqrt(4^2-4(1)(6)))/2(1) r=(16 +/- Sqrt(-8)) r=8 +/- Sqrt(2)*i, alpha=8, Beta=Sqrt(2) y(0)=2, e^(8*0)*(c1*cos(0)+c2*sin(0))=c2=2

*asked on July 10, 2007* -
## Physics check

A performer, seated on a trapeze, is swinging back and forth with a period of 9.55 s. If she stands up, thus raising the center of mass of the trapeze + performer system by 20.0 cm, what will be the new period of the system? Treat trapeze + performer as a

*asked on April 12, 2007* -
## Physics - KE/Inertia

The rigid body shown in Figure 10-66 (it is a triangle with the upper mass = to M and the bottom two corners/masses equal to 2M. The bottom side length equals .70 cm with point P in the middle of the side and the other two sides equal .55 cm) consists of

*asked on March 25, 2007* -
## calc check: euler's method

Given the differential equation: dy/dx = y(1+x), y(0)=1, Use Euler's method with step size .1 to approximate y(.3). y' = y(1+x), y'(0) = 1(1+0)=1 ->the solution has slope 1 at the point (0,1); x0=0, y0=1, h=0.1, F(x,y)=y(1+x) y1=y0+h*F(x0,y0) y1=1 +

*asked on July 1, 2007* -
## Calculus - Orthogonal Trajectories

Find the orthogonal trajectories of the family of curves: y = k*(e^-x) --------------- so k = y/(e^-x) differentiating we get: 1 = -k(e^-x)*(dx/dy) 1/(dx/dy) = -k(e^-x) dy/dx = -k(e^-x)...substituting for k: dy/dx = -(y/(e^-x))*(e^-x) dy/dx = -y

*asked on June 26, 2007* -
## Calculus

Find the exact coordinates of the centroid. y = sqrt[x], y = 0, x = 9. -------------- Is this basically 1/4 of an oval/ellipse? If so then the area would be: pi*9*3, correct? So the X coordinate would equal: 1/Area * Integral from 0 to 9 of (x*f(x))*dx

*asked on June 18, 2007* -
## Calculus

A steady wind blows a kite due west. The kite's height above ground from horizontal position x = 0 to x = 80 ft is given by the following. y = 150 - (1/40)(x-50)^2 Find the distance traveled by the kite. y = 150 - (1/40)(x-50)^2 y = 150 -

*asked on June 15, 2007* -
## Physics Phase Constant

Figure A [[which i tried to recreate below]] is a partial graph of the position function x(t) for a simple harmonic oscillator with an angular frequency of 1.1 rad/s. [a] ............x(cm).............. .................5-|-.................

*asked on April 4, 2007* -
## Physics SHM

An automobile can be considered to be mounted on four identical springs as far as vertical oscillations are concerned. The springs of a certain car are adjusted so that the oscillations have a frequency of 4 Hz. (a) What is the spring constant of each

*asked on April 4, 2007* -
## Re: Physics/Math

A 17 N horizontal force F pushes a block weighing 6.0 N against a vertical wall. The coefficient of static friction between the wall and the block is 0.68, and the coefficient of kinetic friction is 0.48. Assume that the block is not moving initially. Will

*asked on February 10, 2007* -
## Physics - Torque

A particle is acted on by two torques about the origin: T1 has a magnitude of 4.3 N*m and is directed in the positive direction of the x axis, and T2 has a magnitude of 3.2 N*m and is directed in the negative direction of the y axis. What are the magnitude

*asked on March 31, 2007* -
## Physics

A 1.1 kg particle-like object moves in a plane with velocity components Vx = 30 m/s and Vy = 90 m/s as it passes through the point with (x, y) coordinates of (3.0, -4.0) m. (a) What is its angular momentum relative to the origin at this moment? _____

*asked on March 30, 2007* -
## PHYSICS, still cant get it

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at 40.00 m/s relative to

*asked on February 27, 2007* -
## Re: Physics/Math

A sphere of mass 2.7 x 10^-4 kg is suspended from a cord. A steady horizontal breeze pushes the sphere so that the cord makes a constant angle of 41 degrees with the vertical. Find the magnitude of the push provided by the breeze and Find the tension in

*asked on February 18, 2007* -
## Physics/Math

A 17 N horizontal force F pushes a block weighing 6.0 N against a vertical wall. The coefficient of static friction between the wall and the block is 0.68, and the coefficient of kinetic friction is 0.48. Assume that the block is not moving initially. Will

*asked on February 10, 2007* -
## Physics/Math

A 3.0 kg block, initially in motion, is pushed along a horizontal floor by a force F of magnitude 18 N at an angle = 45° with the horizontal. The coefficient of kinetic friction between the block and floor is 0.25. (Assume the positive direction is to the

*asked on February 10, 2007* -
## PHYSICS

The pressure and volume of an ideal monatomic gas change from A to B to C. From A to B, volume remains 0.400 and pressure rises to 4.00x10^5. From B to C, volume changes from 0.400 to 0.200 while pressure remains the same. There is a curved line between A

*asked on December 1, 2015* -
## calc check: average value

Find the average value of the function "f(x) = x^2 sqrt(1+x^3)" on the interval [0,2]. and this is what i did.. please check for mistakes. thanks :D f(x) = x^2 sqrt(1+x^3), [0,2] f ave = (1/(b-a))*inegral of a to b for: f(x) dx f ave = (1/(2-0))*integral

*asked on June 30, 2007* -
## calc: simpson's rule & arc length

i'm still getting this question wrong. please check for my errors: Use Simpson's Rule with n = 10 to estimate the arc length of the curve. y = tan x, 0

*asked on June 13, 2007* -
## calc: arc length

Posted by COFFEE on Monday, June 11, 2007 at 11:48pm. find the exact length of this curve: y = ( x^3/6 ) + ( 1/2x ) 1/2

*asked on June 12, 2007* -
## Physics - Pendulums

A uniform circular disk whose radius R is 32.0 cm is suspended as a physical pendulum from a point on its rim. (a) What is its period of oscillation? __ s (b) At what radial distance r < R is there a point of suspension that gives the same period? __ cm in

*asked on April 12, 2007* -
## Physics - angular acceleration

An object rotates about a fixed axis, and th angular position of a reference line on the object is given by THETA(t)=0.4e^2t, where THETA is in radians, and t is in seconds. [a.] what is the object's angular acceleration at t = 2 s? ..this is my work so

*asked on April 8, 2007* -
## Physics

A sanding disk with rotational inertia 1.1 x 10^-3 kg*m^2 is attached to an electric drill whose motor delivers a torque of 6 Nm about the central axis of the disk. What are the following values about the central axis at the instant the torque has been

*asked on March 30, 2007* -
## Re: PHYSICS

A stationary block explodes into two pieces L and R that slide across a frictionless floor and then into regions with friction, where they stop. Piece L, with a mass of 2.0 kg, encounters a coefficient of kinetic friction µL = 0.40 and slides to a stop in

*asked on February 27, 2007* -
## Physics/Math

What are the x and y components of a vector a in the xy plane if it's direction is 215 degrees counterclockwise from the positive direction of the x axis and its magnitude is 12.9 m ? you would be in the third quadrant, so both x and y are negative. The

*asked on February 18, 2007* -
## Physics/Math

Calculate the ratio of the drag force on a passenger jet flying with a speed of 750 km/h at an altitude of 10 km to the drag force on a prop-driven transport flying at one-fifth the speed and half the altitude of the jet. At 10 km the density of air is

*asked on February 10, 2007* -
## Physics.. last one.

Four balls are suspended by cords. The longer, top cord loops over a frictionless pulley and pulls with a force of magnitude 95 N on the wall to which it is attached. The tensions in the shorter cords are T1 = 56.0 N (between ball A & B), T2 = 46.7 N

*asked on February 6, 2007* -
## calculus - derivatives

can you please find the first 5 derivatives for: f(x) = (0.5e^x)-(0.5e^-x) f'(x) = ? f''(x) = ? f'''(x) = ? f''''(x) = ? f'''''(x) = ? thanks :) f(x) = (0.5e^x)-(0.5e^-x) f'(x) = 0.5 e^x + 0.5 e^-x f''(x) = 0.5 e^x - 0.5 e^-x f'''(x) = 0.5 e^x + 0.5 e^-x

*asked on July 30, 2007* -
## calculus - ratio test

Posted by COFFEE on Sunday, July 29, 2007 at 6:32pm. infinity of the summation n=1: (e^n)/(n!) [using the ratio test] my work so far: = lim (n->infinity) | [(e^n+1)/((n+1)!)] / [(e^n)/(n!)] | = lim (n->infinity) | [(e^n+1)/((n+1)!)] * [(n!)/(e^n)] | = lim

*asked on July 29, 2007* -
## Calculus - Taylor

could you please help me with solving this problem? #1) Find the Taylor polynomial Tn(x) for the function 'f' at the number 'a'. f(x) = sqrt(3+x^2) ; a=1; n=2; my work so far: f (x) = sqrt(3+x^2) = (3+x^2)^(1/2) f ' (x) = (1/2)(3+x^2)^(-1/2) f '' (x) =

*asked on July 28, 2007* -
## Math/Calculus

Please take a look at my work below and provide a good critique: Solve the differential equation using the method of undetermined coefficients or variation of parameters. y'' - 3y' + 2y = sin(x) yc(x)= c1*e^2x+c2*e^x y"-3y'+2y=sin(x) r^2-3r+2=0

*asked on July 11, 2007* -
## Math

A series circuit contains a resistor with R = 24 , an inductor with L = 2 H, a capacitor with C = 0.005 F, and a generator producing a voltage of E(t) = 12 sin(10t). The initial charge is Q = 0.001 C and the initial current is 0. Find the charge at time t.

*asked on July 10, 2007* -
## Calculus

Graph the curve and find its exact length. x = e^t + e^-t, y = 5 - 2t, from 0 to 3 Length = Integral from 0 to 3 of: Sqrt[(dx/dt)^2 + (dy/dt)^2] dx/dt = e^t - e^-t, correct? dy/dt = -t^2 - 5t, correct? So: Integral from 0 to 3 of Sqrt[(e^t - e^-t)^2 +

*asked on June 13, 2007* -
## Math/Euler's Method

Consider a cooling cup of coffee whose initial temperature is 205°. The room temperature is held at 70°. Suppose k = 1/16. Let y be the temperature, and y' its time derivative. ----------------------------------- I have the differential equation: y' =

*asked on June 7, 2007* -
## Math/Calculus

How would I integrate the following: (2x^2 + 5)/((x^2+1)(x^2+4))dx I think I would start with making it a sum of two partial fractions.

*asked on May 29, 2007* -
## Math/Calculus

How would I integrate the following by parts: Integral of: (x^2)(sin (ax))dx, where a is any constant. Just like you did x^2 exp(x) below. Also partial integration is not the easiest way to do this integral. You can also use this method. Evaluate first:

*asked on May 28, 2007* -
## physics - sound level

For two sounds whose sound levels differ by 69 dB, find the ratios (greater value / smaller value) of the following values. (a) the intensities Intensity Final/Intensity Initial = log^-1 (69 / 10) = 7.9x10^6 (b) the pressure amplitudes (c) the particle

*asked on April 21, 2007* -
## Physics - SHM

An oscillating block-spring system has a mechanical energy of 1.00 J, an amplitude of 11.2 cm, and a maximum speed of 1.08 m/s. (a) Find the spring constant. ___ N/m (b) Find the mass of the block. ___ kg (c) Find the frequency of oscillation. ___ Hz .. im

*asked on April 12, 2007* -
## Physics Phase Constant

..im really stuck on this. can someone please explain? ------- Figure A [[which i tried to recreate below]] is a partial graph of the position function x(t) for a simple harmonic oscillator with an angular frequency of 1.1 rad/s. [a].....x(cm).......

*asked on April 4, 2007* -
## Physics - KE/Inertia

The rigid body shown in Figure 10-66 (it is a triangle with the upper mass = to M and the bottom two corners/masses equal to 2M. The bottom side length equals .70 cm with point P in the middle of the side and the other two sides equal .55 cm)consists of

*asked on March 26, 2007* -
## Re: PHYSICS

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at 40.00 m/s relative to

*asked on February 27, 2007* -
## Physics/Math

A bicyclist travels in a circle of radius 35.0 m at a constant speed of 7.00 m/s. The bicycle-rider mass is 72.0 kg. Calculate the magnitude of the force of friction on the bicycle from the road. Calculate the magnitude of the net force on the bicycle from

*asked on February 12, 2007* -
## Re: Physics/Math

A 3.0 kg block, initially in motion, is pushed along a horizontal floor by a force F of magnitude 18 N at an angle = 45° with the horizontal. The coefficient of kinetic friction between the block and floor is 0.25. (Assume the positive direction is to the

*asked on February 10, 2007* -
## Physics

Four balls are suspended by cords. The longer, top cord loops over a frictionless pulley and pulls with a force of magnitude 95 N on the wall to which it is attached. The tensions in the shorter cords are T1 = 56.0 N (between ball A & B), T2 = 46.7 N

*asked on February 6, 2007* -
## calculus - power series ASAP please :)

using power series, integrate & evaluate to 4 dec. places integral from 0 to 1: sin x^2 dx i'm REALLY stuck on this. and i need help asap.. what is the inverse of "sin x^2" so that i could have it in a fraction that will fit the power series equation? and

*asked on July 31, 2007* -
## Calculus - ratio test

infinity of the summation n=1: (e^n)/(n!) [using the ratio test] my work so far: = lim (n->infinity) | [(e^n+1)/((n+1)!)] / [(e^n)/(n!)] | = lim (n->infinity) | [(e^n+1)/((n+1)!)] * [(n!)/(e^n)] | = lim (n->infinity) | ((e^n)(e^1)(n!)) / ((n+1)(n!)(e^n)) |

*asked on July 29, 2007* -
## Math

i'm a bit stuck with this.. 145/18 = x + x^2 what does x equal to? multiply each term by 18, then re-arrange to get 18x^2 + 18x - 145 = 0 This quadratic does not factor, so use the quadratic formula to get your two answers.

*asked on July 27, 2007* -
## Calculus - Second Order Differential Equations

Solve the initial-value problem. y'' + 4y' + 6y = 0 , y(0) = 2 , y'(0) = 4 r^2+4r+6=0, r=(16 +/- Sqrt(4^2-4(1)(6)))/2(1) r=(16 +/- Sqrt(-8)) r=8 +/- Sqrt(2)*i, alpha=8, Beta=Sqrt(2) y(0)=2, e^(8*0)*(c1*cos(0)+c2*sin(0))=c2=2 y'(0)=4, c2=4

*asked on July 9, 2007* -
## Calculus - Second Order Differential Equations

Solve the boundary-value problem. y''+5y'-6y=0, y(0)=0, y(2)=1 r^2+5r-6=0, r1=1, r2=-6 y=c1*e^x + c2*e^-6x y(x)=c1*e^x+c2*e^-6x y'(x)=c1*e^x-6*c2*e^-6x y(0)=c1+c2=0, c1=-c2 y(2)=c1*e^2+c2*e^(-12)=1 -c2*e^2-6c2*e^(-12)=1 -c2(e^2-6*e^-12)=1

*asked on July 9, 2007* -
## calc check please?

Given the differential equation: dy/dx = y(1+x), y(0)=1, Use Euler's method with step size .1 to approximate y(.3). ... please check this for me! no one has responded to this question yet.. thanks. y' = y(1+x), y'(0) = 1(1+0)=1 ->the solution has slope 1

*asked on July 2, 2007* -
## calc check: curve length

Find the length of the curve y=(1/(x^2)) from ( 1, 1 ) to ( 2, 1/4 ) [set up the problem only, don't integrate/evaluate] this is what i did.. let me know asap if i did it right.. y = (1/(x^2)) dy/dx = (-2/(x^3)) L = integral from a to b for:

*asked on July 2, 2007* -
## Calculus - Seperable Equations

Solve the separable differential equation (dy/dx)=y(1+x) for y and find the exact value for y(.3). dy/dx = y(1+x) dy/y = (1+x)dx Integral (dy/y) = Integral (1+x)dx ln (y) = x + (1/2)x^2 + C y = e^(x + (1/2)x^2 + C) y(0.3) = e^(0.345 + C) I am stuck here.

*asked on June 26, 2007* -
## Calculus

A steady wind blows a kite due west. The kite's height above ground from horizontal position x = 0 to x = 80 ft is given by the following. y = 150 - (1/40)(x-50)^2 Find the distance traveled by the kite. y = 150 - (1/40)(x-50)^2 y = 150 -

*asked on June 13, 2007* -
## Math/Calculus

How would I evaluate the following integral by using integration by parts? Integral of: (t^3)(e^x)? You mean (x^3)(e^x)? x^3 exp(x) dx = x^3 d[exp(x)] = d[x^3 exp(x)] - exp(x) d[x^3] = d[x^3 exp(x)] - 3 x^2 exp(x) dx So, if you integrate this you get x^3

*asked on May 28, 2007* -
## Math/Calculus

How would I solve the following integral with the substitution rule? Integral of: [(x^3)*(1-x^4)^5]dx Put 1-x^4 = y Then -4x^3 dx = dy Integral is then becomes: Integral of -1/4 y^5 dy ok, thanks a lot! I got it now.

*asked on May 28, 2007* -
## Math/Calculus #2

Integrate: 1/(x-sqrt(x+2) dx I came up with: (2/3)(2*ln((sqrt(x+2))-2)+ln((sqrt(x+2))-1)) but it keeps coming back the wrong answer even though I integrated correctly. Is there a way to simplify this answer, and if so, how? I found: Ln[x-sqrt(x+2)] +

*asked on May 27, 2007* -
## Math/Calculus

Integrate: (2x^2+5)/((x^2+1)(x^2+4)) I came up with: (tan^-1)(x)-(1/2)((tan^-1)(2/x)) but it keeps coming back the wrong answer even though I integrated correctly. Is there a way to simplify this answer, and if so, how? Your answer is correct, but I think

*asked on May 27, 2007*

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