00:01
So we have a train going around a curve that presumably doesn't have any banking, but the radius of this curve, we can just call r.
00:11
And we're told the train is traveling at a speed of 216 kilometers an hour.
00:17
And we want to know what's the smallest this curve can be so that the acceleration the train experiences is no greater than 0 .05 times the acceleration due to gravity.
00:29
So, first off, let's convert this to 216 kilometers an hour to meters a second, which is just 60 meters per second.
00:41
And this acceleration, 0 .05 times 9 .8, is 0 .49 meters per second square.
00:50
So what we have, then, is this acceleration is going to equal v squared over r.
00:54
So the radius we want is v squared over a, because that's our centrifugal.
00:59
Acceleration formulas v squared over r so we'll have 60 squared divided by 0 .49 and this gives us a radius of 7 ,346 .94 meters given this speed.
01:19
So quite large and then that's part a of the problem.
01:23
Sorry, maybe i should put it up somewhere else.
01:27
Let's say part b, though...