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  1. B

    Peicewise limit help

    ok so lim(x->1+)=(1+1)=2 lim(x->1-)=(1+1)=2 so the limit exists, i don't understand how that helps in finding the overall limit of F(x) at 1.
  2. B

    Peicewise limit help

    sorry that should be x+1
  3. B

    Peicewise limit help

    F(x)= 2x^2, x<1 3, X=1 X+, x>1 Find lim(x-->1) f(X) f(1)= not exactly sure how to do this. would not f(1) be just 3, since it is defined as that in the function. I am not sure about how to take that limit. Thanks
  4. B

    Limit lim(x->pi/4) tan(2x) =tan(pi/2)

    lim(x->pi/4) tan(2x) =tan(pi/2) wat to do after this, it is undefined
  5. B

    Biology help please

    what is the difference between amino acids on their own and amino acids that have been incorporated into a polypeptide chain? My answer is that amino acids on their on do nothing. However when they interact they create a protein which eventually takes on a particular function. why does...
  6. B

    Help-physics to get started

    Hi Doc Al, Almost solved it the a i use here will be angular acceleration so net torque=T*R or Ia=T*R Ia=(mg-mRa)R Ia=mgr-mR^2a Ia+mgR^2a=mgr a(Ia+mR^2)=mgr a=mgr/I+mR^2 for acceleration the tension is a=mR^2g/(I+mr^2)
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    Help-physics to get started

    An object of mass m is tied to a light string wound around a wheel that has a moment of inertia I and radius R. The wheel bearing is frictionless and the string does not slip. find the tension and the acceleration of the object. I think mg-T=ma and that I=MR^2 thats all i know can...
  8. B

    Help-santa claus problem

    ok i understand. What i don't understand is how to write a "physics story". I guess that i have to describe what's going on in the problem?
  9. B

    Help-santa claus problem

    Chubby Santa(mass 100kg) decides to have some fun and slides 9.0 m down a snowy roof)starting from rest. There is a 135 n fricitional force between santa and the roof. After sliding the 9.0 meters he collides with and clings to, an elf (mass 50kg) who was sitting on the roof edge. They both fall...
  10. B

    Check answer for momentum prob

    yah i got the answer as -.57m/s. thnx
  11. B

    Check answer for momentum prob

    then i would get a negative v since v'=325-450/40=-3.125m/s
  12. B

    Check answer for momentum prob

    so the m_{2}v_{2) becomes negative? i don't understand what u mean by "direction matters"
  13. B

    Check answer for momentum prob

    A 130-KG tackler moving at 2.5 m/s meets head on(and tackles) a 90 k-g halfback moving at 5.0 m/s. What will be their mutual speed immediatley after the collison? someone please check my work m_{1}v_{1}+m_{2}v_{2}=v'(m_{1}+m_{2}) so v'=\frac{325+450}{220} v'=3.52 m/s
  14. B

    Billiard ball Momentum help

    Hey Doc Al, thnx for helping me through this process :). I got \theta_{2}=-33 v'_{B}=.81 m/s
  15. B

    Billiard ball Momentum help

    yes i plugged in numbers and i got .068=v'_{B}\cos\theta'_{2 -.72=v'_{B}\sin\theta'_{2} thats all i can do to simplify
  16. B

    Billiard ball Momentum help

    can someone help me in simplifying these equations? thnx
  17. B

    Billiard ball Momentum help

    well I am not sure whether this problem has a definite answer(as in 1.2 or 3.4 etc)or whther I am suposed to solve in terms of variables
  18. B

    Billiard ball Momentum help

    A billiard ball of mass m_{A}=0.400kg moving with a speed v_{A} =1.8m/s strikes a second ball, initially at rest, of mass M_{B}=0.500kg. As a result of the collision, the first ball is deflected off at an angle of 30\deg with a speed of v'_{A}=1.1 m/s. a) taking the x-axis as the positive...
  19. B

    Spring help-please

    So the kinetic energy would be 1/2*184(0.052)^2=.25J
  20. B

    Spring help-please

    so the total energy would be 1/2 KA^2
  21. B

    Problem of Springs

    thnx a lot man
  22. B

    Problem of Springs

    yes but i get v=0 when i do the derivative. is this correct? thnx for ur help
  23. B

    Problem of Springs

    ok so i have to take the derivative x=3.0\cos(5\pi t+\pi) so the derivative of that would be 3.0*-\sin(5\pi(0.5)+\pi)*d/dx(5\pi(0.5)+\pi
  24. B

    Problem of Springs

    yes i need to calculuate velocity, but i don't know how to get it.
  25. B

    Problem of Springs

    I have no idea what you are talking about? are my other answers correct?
  26. B

    Problem of Springs

    A particle has displacement given byx=3.0\cos(5\pi t+\pi) where x is in meters and t in seconds A)What are the frequency ,F, and the period,T, of motion B)What is the greatest distance the particle travels from equlibrium c)Where is the particle at time t=0?t=0.5(s) D)What is the velocity...
  27. B

    Spring help-please

    At t=0, a 650-g(0.65kg) mass at rest on the end of a horizontal spring(k=184n/m) is struck by a hammer which gives it an initial speed of 2.26 m/s. Determine (a) the period and frequency of the motion (b)the amplitude (c)the maximum acceleration (d) the position as a function of time (e) the...
  28. B

    Integration help

    hey everyone i need help with this antiderivative \int\sec^{2}x\tan^{4}x my guess is that it is tan^5(x)/5
  29. B

    Spring mass help-desperate

    ok i got v=1.59 for part A and v=1.18 for part b how do i find the total energy of the system?
  30. B

    Spring mass help-desperate

    ok i found K as 1.27 and plugged it back so \ so i got the velocity as 0.28m/s is this right so then the velocity from 0.1 m from equibium would be .78m/s c) total energy of the system would be 1/2KA^2=0.014--dosent make sense thnx
  31. B

    Spring mass help-desperate

    spring mass help--desperate A 0.35-kg mass at the end of the vibrates 3 times per second with an amplitude of 0.15m. Determine (a)the velocity when it passes the equilibrum point (b)the velocity when it is 0.10m from the equilibrum point(c)the total energy of the system(d)the equation...
  32. B

    Hyperbolic help

    yah I found the answer as x=ln[1+sqt2]----thanks for your help
  33. B

    Hyperbolic help

    at what point on the curve y=\cosh x does the tangent have slope 1 I have no idea how to approach this problem my work 1=\sinh x\frac{dy}{dx} \frac{1}{sinh x}=\frac{dy}{dx}
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    Hyperbolic function proof

    I need help proving this hyperbolic function Prove that \tan^{-1}\hbar {x}=\frac{1}{2}\ln\frac{1+x}{1-x} my work x=e^y-e^-y/e^y+e^-y (e^y+e^-y)x=e^y-e^-y 0=e^y-e^-y-xe^y+xe^-y e^y(e^y-e^-y-xe^y+xe^-y) e^2y-x(e^2y)-1+x=0 I know i have to use the quadratic equation here
  35. B

    Challenging Physics

    Hey guys I need help on this one physics problem. I did the problem but I am not sure whether I did it right. Please make comments if i did the problem wrong. Thank you. A projectile is shot from the edge of a cliff 125 M above ground levbel with an inital speed of 65 m/s at an angle of 37...
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