00:01
So in this problem, we have a car, which is driving in some perfectly circular path.
00:07
And we want to ask, where is the net force on the car? so it's driving on a path from some middle.
00:15
We can have the car there, which is traveling in a path.
00:19
It's a constant circle and constant speed.
00:33
So to look at this, first we'll look at wendy motion of the car and then look at it in rotational motion.
00:40
So imagine we have the car, which is traveling for like such at a constant speed.
00:48
What is the net force on the car? well, by newton's law of inertia, the net force is zero.
00:54
Because if it's constant speed, then the acceleration, a, is equal to zero.
01:04
So by newton's second law, also we say that force is equal to mass times acceleration, and this is the net force, or we can call it the sum of forces.
01:14
If the acceleration is equal to zero, then that means.
01:17
Means the sum of forces is equal to zero.
01:19
So the net force, therefore, must be zero.
01:25
And so this car in a straight line, moving continues on forever at the same speed.
01:31
And that's kind of like what's happening in this rotating, in this car driving in a circle, because it's a constant speed...