 #1
Tony Zalles
 22
 0
Hi,
Ok I have a bit of difficulty workin this Physics Mechanics problem.
Ok here is the problem....
The coordinates of a plane flying in the xyplane are given as functions of time by:
X = 2.0m  at
Y = bt^2
where a = 3.0 m/s and b = 2.5 m/s^2
A) Calculate the velocity vector as a function of time.
B) Calculate the acceleration vector as a function of time.
C) Calculate the magnitude and direction of the bird's velocity at t=2.9s.
D) Calculate the magnitude and direction of the bird's acceleration a t=2.9s.
Ok here's what I've accomplished so far...
Now I have these formulas.
Ok, now I believe you find a(x) and a(y) by taking the derivatives of bt^2 and 2.0  at, thus getting 2bt and a.
But I don't quite understand what the question (part A) is asking, when they want the velocity vector as a function of time.
I'm guessing its this: v(t) = 3.0i + 5.0tj
if this is so then the acceleration vector (part B) is expressed as:
a(t) = 5.0j
So based on this I'm guessing part C is:
v(2.9s) = 5.83 m/s
but I'm not sure if this is correct either since part c asks for 'magnitude and direction', I feel like I'm missing something to my answer...
Lastly following all the above part D should be:
a(2.9s) ≈ 5.0 m/s^2
So....I hope I can get some insight into this problem, I hope someone can help, and give me some guidance.
Thanks.
Ok I have a bit of difficulty workin this Physics Mechanics problem.
Ok here is the problem....
The coordinates of a plane flying in the xyplane are given as functions of time by:
X = 2.0m  at
Y = bt^2
where a = 3.0 m/s and b = 2.5 m/s^2
A) Calculate the velocity vector as a function of time.
B) Calculate the acceleration vector as a function of time.
C) Calculate the magnitude and direction of the bird's velocity at t=2.9s.
D) Calculate the magnitude and direction of the bird's acceleration a t=2.9s.
Ok here's what I've accomplished so far...
Code:
NOTE:
/^ a(x) = a subscript x
y /  a(y) = a subscript y
 /  i = unit vector component, xaxis
 a /  j = unit vector component, yaxis
 / a(y)j
 / 
 /θ 
bt^2  *>
 a(x)i


2.0  at x
Now I have these formulas.
Code:
a = √((a(x))^2 + (a(y))^2)
tan θ = a(y)/a(x)
a(x) = a cos θ
a(y) = a sin θ
a = a(x)i + a(y)j
But I don't quite understand what the question (part A) is asking, when they want the velocity vector as a function of time.
I'm guessing its this: v(t) = 3.0i + 5.0tj
if this is so then the acceleration vector (part B) is expressed as:
a(t) = 5.0j
So based on this I'm guessing part C is:
v(2.9s) = 5.83 m/s
but I'm not sure if this is correct either since part c asks for 'magnitude and direction', I feel like I'm missing something to my answer...
Lastly following all the above part D should be:
a(2.9s) ≈ 5.0 m/s^2
So....I hope I can get some insight into this problem, I hope someone can help, and give me some guidance.
Thanks.