00:01
In this question, we have this plank on roller problem.
00:04
So there are three parts in this question.
00:11
We are given that the cylinders row without slipping on a flat surface, there's also no slipping between the cylinders and the plank.
00:19
So we need to find an initial acceleration of the plank.
00:22
At the moment, the rollers are equidistant from the ends of the plank.
00:27
Okay, so resolution, okay, in part a.
00:38
So we need to draw the free body diagrams for the plank, for the plank and the roller.
00:53
Yeah.
00:53
So for the plank.
00:59
Okay, so there's a force to the right.
01:04
That's a applied force.
01:06
And then there are two frictional force that's going to point to the left.
01:12
Okay.
01:12
Then there's two frictional force.
01:12
That's going to point to the left.
01:14
Okay.
01:16
Then the free body diagram for the ruler.
01:25
Okay, so i'm going to call this f1.
01:37
Okay, there'll be friction f2, no, this is f1.
01:43
Okay, because they are pairs or with the friction that's on the plank.
01:49
And then i'm also going to assume that there's a friction to the right, f2, that's by the ground on the roller.
01:58
Okay.
01:59
Okay.
02:00
So you apply newton's second law on the plank for the plank or the plank okay so we have f minus 2 f1 is equal to bm times a p okay and then we will write the newton's second law equation for the roller okay, so we have f1 plus f2 because to small m times aar.
03:08
And then we are going to have rotational motion.
03:17
Newton's second law for the rotational motion of the roller.
03:36
Okay, so this is equal, this equation looks like.
03:41
So we know that it's going to rotate...