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# Thrust and Pressure: Increasing pressure by decreasing Area

Thrust is defined as the force acting normal to a surface. Pressure is the thrust acting per unit area.

# P=F/A

The equation suggests that the pressure is inversely proportional to area. We can increase the pressure for a given force by decreasing the area. Here are some examples.

## Cutting Tools

Cutting tools have sharp edges with very low area so that high pressure

can be applied by a small force. You can realise this if you try to cut a tomato with a blunt knife and try again after sharpening it.

## Nails and Drawing Pins

Nails and pins have sharp ends so that it can pierce into wooden boards and walls easily by applying a small force.

## In a Karate Punch

In martial arts, the normal punch is executed in such a way that only two knuckles are hitting the target so that maximum pressure can be imparted.

If the entire flat portion of the fist is used, the pressure will be very much less and the opponent will not be hurt much. Punch is only just one of the many attacks in Karate. You can analyse the various attacks and blocks with a view to find the application of pressure in it.

TRY to find out more examples where we decrease area to increase pressure.

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