00:01
All right, so we've got this position function for a race car, and then this is the position t seconds after the brakes are first applied.
00:11
So first we want to find an expression for the car's velocity.
00:15
So velocity is going to be the derivative of the position function.
00:22
So using the power rule, that's just 120, t to the zero, minus bring that two down in front, so 10, t to the 1.
00:30
Okay, there's the velocity function.
00:33
Next, we want to find the velocity when the car's brakes were first applied.
00:39
So that would be the velocity at zero.
00:42
So we put in t equals zero and we get 120 and this is going to be in feet per second.
00:49
So that's quite fast.
00:51
And then the car's stopping distance...