Tuesday, 11 October 2011

5.4 Starter 2 explained

animation - why a drawing pin works.swf Download this file

5.4 Starter 2 explained


· Your finger pushes on the pin and the pin pushes back on your finger
· N3L tells us that all these two forces are equal in size
· The pin pushes on the wall and the wall pushes back on the pin
· N3L tells us that all these two forces are also equal in size
· If the surface area is large then the force is spread over a large area and the pressure is low
· If the surface area is small then the force is spread over a small area and the pressure is high
· You would like the pressure on your finger to be low and the pressure on the wall to be high
· The other way round is painful!

No comments:

Post a Comment