Unit Tangent Vectors for Position Vectors: Finding T(t) for Given Values of t

AI Thread Summary
To find the unit tangent vector T(t) for the given position vectors, the derivative r'(t) must be calculated and then divided by its magnitude |r'(t)|. For r(t) = (cos(5t), sin(5t)), the user struggles with T(pi/4) and seeks clarification on their calculations. For r(t) = (t^2, t^3), the user reports obtaining (1, 1) for T(1) but is uncertain about the correctness of their results. The discussion highlights confusion over the steps involved in deriving the unit tangent vectors and the need for accurate calculations to avoid errors. Overall, the focus is on correctly applying the derivative and magnitude to find T(t) for various functions.
weckod
Messages
13
Reaction score
0
positon vectors r(t) find the unit tangent vectors T(t) for the given value of t

r(t) = (cos5t, sin5t)
T(pi/4) = ( , )

r(t) = (t^2, t^3)
T(1) = ?

r(t) = e^5t i + e^-1t j + t k
T(2) = ? i+ ? j+ ? k

now the to find it i use r'(t)/lr'(t)l
I did that, but i get wrong answers i don't know what I am doing wrong because all i c is that is how u find the unit tangent vectors... someone please help me and explain what u did.. thanks alot!
 
Physics news on Phys.org
the derivative is the tangent vector.
then divide it by its magnitude to get unit tangent vector.
 
I did that and the damn computer say i got the wrong answers... like the 1st one i took it derivative then i divid it by its magnitude which is squaring everything and sq rt it right that's what i did..
 
give the answer that you have found for the first one.
 
well i worked out the second one i got (1, 1) i really I am doing something stupid
 
i get 2/sq rt of 13, 3/ sq rt of 13
what is wrong with your steps?
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top