Within the funnel of a tornado the air pressure is much...

within the funnel of a tornado the air pressure is much lower than normal about 200 mbar as compared to the normal value of 1010 mbar. suppose that such a tornado suddenly envelops a house; the air pressure inside the house is 1010 mbar and the pressure outside suddenly drops to 200 mbar. This will cause the house to burst explosively. what is the net outward pressure force on a 12 m x 3 m wall of this house? is the house likely to suffer less damage if all the windows and doors are open?

Transcript

00:01 Here we're going to look at what pressure is, and in particular, gas pressure, and why a difference in gas pressure between one side of a solid object and another can cause quite a bit of damage.

00:16 But pressure is defined to be force per unit area, that force acts perpendicular to the area.

00:30 So, for example, let's say that we have a wall standing there on the ground, and it has air on both sides.

00:42 And we basically have one atmosphere.

00:46 So what that means is that there is a force on one side per unit area would give us one atmosphere, and the same on the opposite side.

01:04 So if those pressures are the same, and of course the areas are the same, the net force on the wall will be equal to zero.

01:17 Now, it could be compressed.

01:19 If the pressure were high enough on either side, it could squeeze the wall and, you know, squish it down a little bit.

01:26 But there won't be a tendency for the wall to move one way or the other.

01:32 But let's see what happens during a storm where the pressure is going to be lowered outside the house.

01:42 And if your windows and doors and all that are closed, this is why many people in a hurricane want to open their windows or during a tornado is to allow the pressure to equalize on the inside and the outside.

01:59 But let's take a wall now, and we'll put it inside the house.

02:07 We won't show all the enclosures and everything.

02:11 But typically during the storm, pressure goes down, just like the parametric pressure.

02:17 And let's make it a very violent storm, so the pressure outside is 200 millie bars.

02:26 A bar is approximately one atmosphere.

02:30 And inside the pressure is a little bit over one atmosphere.

02:40 So 10 .10 millibars are about one atmosphere.

02:45 So you have a very big difference in the force...