00:01
Okay, so it's probably got a meter stick with rotational inertia of 1 3rd ml squared.
00:12
And just the edge is sort of over the table.
00:15
So we want to think about the forces acting on this.
00:17
You've got the force of gravity, which would be mg.
00:24
And there is a normal force from the table here as well.
00:33
They want to know what is the linear acceleration of the far end of the meter stick in terms of g.
00:40
Okay, so we need to think about a couple different things here.
00:43
So number one is net torque is equal to i -alpha.
00:50
Number two is net force is equal to mass times acceleration.
00:58
And number three is acceleration is equal to r -alpha.
01:02
So this is how we relate between linear and rotational acceleration.
01:09
Okay, so if we think about just the net torque here, let's make the pivot right here.
01:15
And that would make our net torque mg times l over 2.
01:23
Okay, and we know that because it's the force times the distance from the pivot.
01:28
So the force is mg, and the distance from the pivot is half the length of the meter stick...