0:00
Hello.
00:02
So this question involves energy conservation.
00:11
So while the person cycles on the pisa, kinetic energy is lost to friction.
00:23
Okay, so kinetic energy is lost to friction in this.
00:26
P is lost to friction.
00:35
Friction on the pza.
00:42
In other words, i can say kinetic energy equals we're done by friction and that's energy conservation.
00:56
So we got this is half mv squared.
01:02
Because the frictional force, so if the frictional force is f, for example.
01:06
Then the distance travel is d.
01:10
So now that we're looking for d for the first part, if you isolate d, you're going to have mv squared over 2f.
01:23
So our mass is 68, our speed is 15.
01:29
Kilometers per hour.
01:32
We need to convert this to meters per second.
01:37
That's going to be so a thousand meters.
01:43
That's one kilometer.
01:47
One hour is going to be 60 times 60 in seconds.
01:53
Everything here squared divided by 2f.
02:01
We don't know the friction of force, so we're just going to, our answer is going to be in terms of the friction.
02:08
So, so let's try this.
02:11
So we got 68.
02:15
I have a bracket.
02:17
So you got 15 ,000 divided by 3600.
02:27
Right, all squared.
02:38
Oops, it's a second...