Here is one more example to hammer on that point: Let F be thevector field F(x,y) = (x + y)i + (xy)j. Let C be the arc of the ellipsex = 3cost, y = 4sint, t = 0...π/2. Then the vector version of thisparametrization isr(t) = (3cost)i + (4sint)j ,the velocity isv(t) = (−3sint)i + (4cost)j ,and we haveCF · T ds =π/2t=0F · v dt =π/2t=0(3cost + 4sint)(−3sint) + ((3cos t)(4sint))(4cost) dt .(I’ll leave it to you and your computer, or table of integrals, to workthis out.)
2006-10-31 02:51:34
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answer #1
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answered by slimshady3in 4
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x= 3 cos t+ 4 sin t
dx/dt= -3 sint + 4 cos t
acceleration= d2x/dt2 = -3 cost - 4sin t= -(3 cost +4sin t)= -x
at the two extreme positions of the particle,
x = x(max) = a = amplitude of the oscillation
at the two extreme positions of the particle,
acceleration= - x(max)= -a
and the amplitude of the oscillation = (3^2 + 4^2)^(1/2)= 5
hence at the two extreme positions, the acceleration of the particle is -5 units, the negative sign indicates that it is opposite directional with displacement.
2006-10-31 13:09:15
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answer #2
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answered by s0u1 reaver 5
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a===5
2006-10-31 10:34:32
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answer #3
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answered by Naughty Boy 2
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easy
the velocity, v, is the derivative of the position, with respect to time. so we have
v = dx/dt=-3sint + 4cost
the acceleration, a, is the derivative of the velocity w respect to time, so we have
a = dv/dt =-3cost -4sint
now, at extreme points of oscillation, by definition the speed is zero
so from above you have
-3sint + 4cost = 0
divide by cost
3tant = 4
tant = 4/3
so t = .927 radians
now plug this into the above function for a, so you have
a (extreme point) = -3cos(.927)-4sin(.927)
a (extreme point) = -5.0
hope this helps
2006-10-31 11:06:06
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answer #4
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answered by AntoineBachmann 5
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Hint:
It is a Maxima - Minima problem at extreme Velocity is Zero and acceleration changes sign. If it is linear, then length of the pendulum is infinite.
Find the equation for pendulum and apply this logical parameter to solve for requested parameters.
2006-10-31 10:46:47
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answer #5
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answered by minootoo 7
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x = 3cos(t) + 4sin(t)
dx/dt = -3sin(t) + 4cos(t) = velocity (v)
d2x/dt2 = -3cos(t) - 4sin(t) = acceleration (a)
set dx/dt = 0 and solve for t:
t ~ 0.9273 radians
plug that t value into the equation for acceleration:
a = 5
2006-10-31 10:55:45
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answer #6
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answered by bromothymol 4
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You should state your question instead of "please answer this?"
I feel like I have wasted valuable time just to educate you in this matter.
2006-10-31 10:38:57
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answer #7
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answered by Anonymous
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yes
Ask me a question
you don't know nothing
2006-10-31 11:03:16
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answer #8
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answered by What's up Doc? (Manu) 4
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