00:01
We've got a shuffleboard disk.
00:03
It starts at rest, and it reaches a speed of six meters per second.
00:16
And it reaches that speed in a distance of 1 .8 meters.
00:29
Okay.
00:36
V squared equals v initial squared, which is zero, plus 2a, d.
00:44
So, the acceleration during that time is going to be v squared over 2d.
01:00
But let's look at what else they're saying here.
01:08
After that period of time or distance, then it slows at 2 .5 meters per second square.
01:24
Okay? okay.
01:27
How much time elapses from when the disc begins to accelerate until it stops? okay.
01:38
So, how much time? oh, and then we need the total distance.
01:50
Well, the distance would be v times t1 plus one half a 1t1 squared.
02:21
So i can use a calculator and graph this.
02:28
I'm going to subtract d on both sides, which will leave me with zero here.
02:37
So i know that v equals 6 and d equals 1 .8, so, y equals v t plus one -half a, which is v squared over 2d, v squared over 2d.
03:11
So i substituted this in for a here times t squared minus d.
03:25
And now i'm looking for where that equals zero.
03:30
That equals zero in 0 .249 seconds.
03:43
249...