- #1
mybsaccownt
- 63
- 0
I'm having some trouble with oscillatory motion...
"A transverse wave on a string is described by the equation
y(x, t) = (0.350 m)sin [(1.25 rad/m)x + (99.6 rad/s)t]
Consider the element of the string at x = 0. (a) What is the time interval between the first two instants when this element has a position of y = 0.175 m? (b) What distance does the wave travel during this time interval?"
ok, the time interval between the first two instants when the element has the same position, that would be the period / 2 right?
so, T = 2Pi/omega omega can be read from the equation and it is 99.6rad/s
so T/2 is what I'm looking for and it is = 0.0315
but that's wrong...the closest answer (on a multiple choice 'quiz') is 31.0 miliseconds, but their answer is exact and so is mine, they are not the same
ok, so maybe i'll use 31ms for part b and see what happens...
well, the distance that the wave would travel would be the angular frequency divided by the wave number k, and all of it multiplied by the period, that would give me the correct units
since omega/k = velocity and velocity * time = distance
the problem is, my answer comes out close to 2.5m and the lowest answers on the multiple choice were 1.68, 1.86, and 3.25, so I'm horribly off but i don't understand why
hints would be appreciated
thanks for your time
"A transverse wave on a string is described by the equation
y(x, t) = (0.350 m)sin [(1.25 rad/m)x + (99.6 rad/s)t]
Consider the element of the string at x = 0. (a) What is the time interval between the first two instants when this element has a position of y = 0.175 m? (b) What distance does the wave travel during this time interval?"
ok, the time interval between the first two instants when the element has the same position, that would be the period / 2 right?
so, T = 2Pi/omega omega can be read from the equation and it is 99.6rad/s
so T/2 is what I'm looking for and it is = 0.0315
but that's wrong...the closest answer (on a multiple choice 'quiz') is 31.0 miliseconds, but their answer is exact and so is mine, they are not the same
ok, so maybe i'll use 31ms for part b and see what happens...
well, the distance that the wave would travel would be the angular frequency divided by the wave number k, and all of it multiplied by the period, that would give me the correct units
since omega/k = velocity and velocity * time = distance
the problem is, my answer comes out close to 2.5m and the lowest answers on the multiple choice were 1.68, 1.86, and 3.25, so I'm horribly off but i don't understand why
hints would be appreciated
thanks for your time