00:01
Hello students, in this question we have four individual subparts.
00:05
So first you have matched correctly with these things.
00:09
So let's rehearse what it is.
00:11
So what is accomplished by this simple pulley? simple pulley.
00:16
What is a simple pulley? so this is a simple pulley setup.
00:20
So that you have two masses like this.
00:23
So if it is balanced that means the mg here must be equal to the mg here.
00:31
The mass must be equal to both of them.
00:33
Both of those must be equal.
00:36
So if the tension in line one must be equal to tension in line two.
00:40
So that is a simple pulley balancing mechanism.
00:43
So it changes direction.
00:45
So you are given it changes direction of force needed to lift the object.
00:49
So simple pulley changes the direction of the force.
00:52
So this was supposed to be the direction of force in this direction.
00:55
This is the direction of force.
00:56
But it just shifted the direction of force downwards.
00:59
So that is true.
01:02
Now coming to the second statement, second question.
01:05
What advantage does screw have over nail? so screw as you know has nail is something that you have.
01:13
You can pound it down to a surface and it will stick onto the surface.
01:18
Right.
01:19
So it will stay there with the friction of the surface.
01:22
But screw is something else.
01:24
Screw is when you have a rotating setup.
01:28
And you will have a projection which is rotating around the setup.
01:33
So that means these projections will penetrate into the surface and you will add more friction...