00:02
So for this function, we're asked about the force of gravity on a point particle at a distance, r, small r, smaller from the radius of the earth, or from the center of the earth, where g is gravitational constant, a physical constant, m is the mass of the earth, and big r is the, i believe, the radius of the earth.
00:36
And we're asked is f continuous and a continuous means as we know by now that we're talking about continuity at every point thankfully you know when we're looking at a in this case we're looking at a piecewise function so that's a little alarming often because we've seen examples where we have some sort of continuous function and then we have a jump and then we have another continuous function like that where it's kind of piecewise defined piecewise like this.
01:06
But, and that's kind of what we have here.
01:10
But thankfully, when small r is equal to r, we will find that actually it's continuous all the way through.
01:20
So we have a continuous piece here and a continuous here, and the continuity is maintained at this junction point, so to speak, at this connecting point where the small r is equal to big r.
01:32
And that's really what we have to show, is that continuity is preserved as you cross...