00:01
So the information from our question is that the mass is 850 kilograms.
00:12
We got the velocity as 45 kilometers per hour.
00:20
What we need to do is to first change this to minutes per second.
00:25
So this, so the 45 is to have that.
00:30
But a kilo is a thousand, okay? that's thousand divided by hours.
00:38
So we need to change the hour to second.
00:41
So 60 minutes is one hour.
00:46
And the 60 seconds is one minute.
00:51
So this is going to give us 12 .5 minutes per second.
01:03
So we're going to use the work energy theory, right? so the work is going to be the changing kinetic energy.
01:16
We know work is force times distance.
01:21
Changing to energy it's going to be half m.
01:25
You got vf squared minus v -i -squared.
01:31
Now because it's going to be stopped, the final velocity is going to be zero.
01:38
So you got force time distance equals half m.
01:43
Oops, you're supposed to be squared, excuse me.
01:47
So that's times negative vi squared.
01:53
So now you're trying to get a force...