00:01
All right, so we have our meter stick here.
00:03
It's getting hit by this little lump of clay at the 90 centimeter mark.
00:06
It has one lump of clay at the 10 centimeter mark already.
00:10
And the first question asks for the momentum before, or the initial momentum of the system before it is struck.
00:22
So before it makes contact.
00:25
And the stick and the initial lump of clay is going to have a.
00:32
Initial momentum of zero, but the moving clay will have a momentum that will have taken into account.
00:39
So the initial momentum of the system is only due to this at the level.
00:43
So we just take its mass times its velocity, 1 .2 meters per second.
00:47
Now, i drew it going to the left, but i treated it like it was going to the right.
00:52
Just reverse my image here for positive values of the velocity.
01:01
So plugging in the mass and the velocity.
01:02
The mass is 50 grams of 0 .05 kilograms.
01:07
Velocity is 1 .2 meters per second.
01:08
We get an initial momentum of 0 .06 kilogram meters per second.
01:14
Number two asks for the kinetic energy.
01:19
And again, that is only due to the moving clay since the rest of the system is at rest.
01:27
So plugging in our values for the mass and velocity into our kinetic energy equation, we get a kinetic energy of 0 .036 joules.
01:37
Number three asks for the initial angular momentum, and this is going to be the moving the clay around the center of mass.
01:47
So right before impact, the center of mass of the system is at the center point of the meter stick.
01:52
So that's going to be the axis of rotation.
01:55
And so we can, this distance r is 40 centimeters away, so 0 .4 meters.
02:01
And the momentum times our of our little ball of clay, we get 0 .025 kilogram meters squared per second.
02:13
Number four, is the momentum conserved? yes.
02:19
There's no outside forces acting on this system, so the momentum will be conserved.
02:27
The energy, however, will not because this lump of clay is sticking to the meter stick.
02:35
And whenever you have an inelastic collision, momentum is not conserved.
02:41
Or sorry, momentum is conserved.
02:43
Energy is not.
02:43
Kinetic energy is not conserved...