00:01
So in this problem, we have this crate on a frictionless surface, and to start, we should draw a free body diagram.
00:05
So we can take the crate, free it from its external reactions and connection to the floor.
00:10
And we don't really see that it's a box.
00:12
We can just represent it as a point.
00:14
We'll keep all the information we need doing that.
00:17
So with the free body diagram, we need to apply all of the forces.
00:21
And so the first one is the two applied forces, f2, which was 33 newton's, f1, which was 50 ,000.
00:33
We also have the weight of the box equal to mg.
00:39
And then resisting the box and falling through the floor is the normal force, which is the contact force from the floor pointed upwards n, which will need to find.
00:49
And then we'll put an axis x and y as in convention.
00:53
So in part a, we want to find the box's acceleration.
00:59
Now we can do this with newton's second law relating the forces we have to acceleration.
01:04
So the sum of forces on this box is equal to m .a.
01:08
Now, what we can recognize here is that this box is going to stay on the floor.
01:13
And the floor, parallel to the x -axis, means that the motion in the y -axis is going to be zero.
01:18
So the only acceleration possible is in the aforementioned x -axis.
01:24
So we can take our sum of motions, sum of forces when newton's psychicot law, and say it only acts in the x direction.
01:32
And then from there, we can just sum up.
01:34
Now we know this 59 newton force is 70 degrees from the horizontal, so we'll need that.
01:40
So we have this f2, 33 newtons, but it's opposite over positive x -axis, so it is negative.
01:48
And then we have some component of our 59 newton force, f1.
01:52
We're going to take the cosine component because it's the component adjacent to the angle, so it should be cosine of the angle, which is 70 degrees...