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GrizzlyChicken
Group Title
The position of a mass on a spring (relative to equilibrium) at time t <= 0 is
x(t) = 2 cos((pi)t) where x is in centimeters and t is in seconds. Answer the ques
tions. Include units!
(a) What is the initial position of the mass?
(b) What is the initial velocity of the mass?
(c) What is the initial acceleration of the mass?
(d) Does the mass initially move towards the wall or away from it?
(e) At what point does the mass rst turn around?
 2 years ago
 2 years ago
GrizzlyChicken Group Title
The position of a mass on a spring (relative to equilibrium) at time t <= 0 is x(t) = 2 cos((pi)t) where x is in centimeters and t is in seconds. Answer the ques tions. Include units! (a) What is the initial position of the mass? (b) What is the initial velocity of the mass? (c) What is the initial acceleration of the mass? (d) Does the mass initially move towards the wall or away from it? (e) At what point does the mass rst turn around?
 2 years ago
 2 years ago

This Question is Closed

goformit100 Group TitleBest ResponseYou've already chosen the best response.0
post the question in physics section Not here @GrizzlyChicken
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
its in my calc book, isn't this math?
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
a) put t = 0 and solve for x b) find x' and put t = 0 and solve for x' c) find x'' and put y = 0 and solve for x''
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
it's both physics and math lol
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
*typo fix* sorry c) find x'' and put t=0
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
wait, its x(t)=2cos((pi)(t))
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
sorry
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
still~ same way of solving :P
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
damn, theres another error, i'm gonna look it all over again, for some reason copy and pasting changed everything
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
at time t is greater or equal to 0. its right now
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
so if i put 0 for t, its 2cos(0)
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
yup, that's the initial position
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
is cos(0)=1?
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
then for b) derivative of 2 is 0 so its all 0
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
maybe
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
no no, find the derivative of the function x
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
so the derivative of 2cos(pi*0)?
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
which uses the product rule (0)(cos...)+(2)(sin(0))
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
and sin(0)=0
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
so the velocity is 0
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
wops sorry i'm here x = 2 cos (pi t) x' = 2 pi sin (pi t)
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
do you know how to derivative?
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
yea, did you use the chain rule?
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
is that why pi is with 2?
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
no chain rule. derivative of cos is sin. pi 's brought out when derivative.
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
dw:1349943924669:dw
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
derivative again for the acceleration equation
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
2cos(pi*t)
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
wait
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
2pi*cos(pi*t)
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
almost correct, but now pi is brought one more time so it's 2 pi^2 cos (pi t)
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
ohhh
 2 years ago

nphuongsun93 Group TitleBest ResponseYou've already chosen the best response.1
x = 2 cos (pi t) x0 = 2 x' = v = 2 pi sin (pi t) v0 = 0 x'' = a = 2 pi^2 cos (pi t) a0 = 2pi^2 and idk how to do d and e
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
does the mass move toward the wall because the acceleration is negative?
 2 years ago

GrizzlyChicken Group TitleBest ResponseYou've already chosen the best response.1
oh, thats alright. you've helped me enough.Thanks!
 2 years ago
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