00:01
All right, hello, in this question we're going to go ahead and look at a mass on a spring.
00:03
We're told that the mass is 0 .520 kilograms and we're told that this is the equation of motion of the mass bobbing on the spring.
00:12
From this we want to determine a few things.
00:15
We want to determine a, the amplitude of oscillation.
00:18
Well, i'm going to go ahead and just start before we actually answer any questions here by writing what this looks like in terms of things we know, in terms of symbols.
00:28
So we're going to have our amplitude times the cosine of our angular frequency times time.
00:33
And for a spring we know that our period is 2 pi times root m over k.
00:40
And we also know that our angular frequency is defined as our 2 pi divided by our period.
00:47
So our angular frequency here is going to be the square root of k over m.
00:52
So with that stuff in mind, we can go ahead and look at our amplitude.
00:56
Well, our amplitude is just going to be the number that's out front.
00:58
So 0 .660 and that's given in meters here.
01:01
So that's our amplitude.
01:03
We're asked to determine the force constant for the spring.
01:06
Well, i just discussed that we have omega is root k over m.
01:10
And we know that in this case that is going to equal a value of 16.
01:15
So we're going to have 16 .0 here.
01:17
If i want to go ahead and solve for k, it's going to be 16 squared times our mass of 0 .520 kilograms.
01:26
That's our spring constant is going to be 133 newtons per meter for this case.
01:32
In part c, we're asked the position of the mass after it's been oscillating for one half of a period.
01:37
So if t equals one half of our period, well, we can answer this conceptually by saying x of one half of a period, a period is if we start on one end, we go all the way over and then we go all the way back.
01:50
That is defined as a one full period there.
01:54
So if we have half a period, we're going to just be on the other end.
01:57
So we're going to be at x equals negative 0 .660 meters...