1. Force versus Pressure
When a force is exerted on an object, pressure is also exerted on the object, but force and pressure are not the same thing.
Force tells you how an object will accelerate. Pressure tells you how it will feel.
or:
Force accelerates. Pressure cuts.

2. versus

3. In your groups Let’s try this activity now:
Using the pin, (while a paper is held by two persons just in contact with the pin head) place a 50 g mass on the paper
Make your observation
Now add another 50g mass
Answer the questions on the activity sheet please

4. You know that the sharp knife cuts more efficiently - Why?
Why does a sharp knife cut better than a dull knife?
The diagram at right shows a sharp knife and a dull knife in contact with a surface (maybe a nice, big piece of chicken).
You know that the sharp knife cuts more efficiently - Why?

5. Notice that the sharp knife has a very small area of contact with the surface, while the dull knife has a much larger area of contact.
If both knives are pushed down with the same force, the sharp knife will exert a much greater pressure on the surface than the dull knife - and pressure cuts.
So, if you are "stuck" with a dull knife, you have to exert much more
force in order to generate enough pressure to cut your chicken, right?

7. Pressure depends on the amount of force and the area over which the force is applied. More force - more pressure. More area - less pressure.
Pressure is directly proportional to force, and inversely proportional to area.

8. So… Pressure (P) is defined as the average force (F) exerted normally per unit area (A) i.e. P = F/A It is a scalar quantity (it has only direction) Its unit is called the Pascal, Pa

9. Applications of principles of pressure…What does pressure have to do with you?

10. It’s not just pressure for exams or home work deadlines

11. Engineering: distribution of pressure in architectural design

12. Or in pressure inside air engines

13. Or for road surfacing: if you are the engineer or purchaser since rollers are based on The levelling/flattening action is achieved through a combination of the size and weight of the vehicle and the rolls: the smooth wheels and the large cylinder or drum fitted in place of treaded road wheels.

14. Medical Physics: Blood pressure (BP) which is he pressure exerted by circulating blood on the walls of blood vessels, and is one of the principal vital signs.

15. Transfer of pressure using a syringe

16. Any person carrying a bag

17. Who didn’t understand that the force exerted over a smaller surface area = greater pressure

18. Or anyone on their feet

20. Has pressure distribution

21. Foot and tendon problems
High-heeled shoes slant the foot forward and down while bending the toes up. The more that the feet are forced into this position, the more it may cause the Achilles tendon to shorten.
This may cause problems when the wearer chooses lower heels or flat-soled shoes. When the foot slants forward, a much greater weight is transferred to the ball of the foot and the toes, increasing the likelihood of damage to the underlying soft tissue which supports the foot.

22. Do you think you’ll be brave enough to try a bed of nails