Class 10 (Science Assignment)

 

Pressure in Everyday Life

Pressure is the force acting normally on a unit area of a surface. It is expressed by the formula:

P= F/A

where P is pressure, F is the normal force, and A is the area over which the force acts. The SI unit of pressure is pascal (Pa).

Pressure depends on both force and area. If the force increases while the area remains constant, pressure increases. Similarly, if the same force acts on a smaller area, the pressure becomes greater. This principle explains why a sharp knife cuts objects more easily than a blunt knife. The sharp edge has a smaller area, so it produces greater pressure.

Liquids also exert pressure. Liquid pressure increases with depth because the weight of the liquid above increases. It also depends on the density of the liquid. For this reason, dams are made thicker at the bottom than at the top. Atmospheric air also exerts pressure on all objects around us. We normally do not notice atmospheric pressure because it acts in all directions and our bodies exert an opposing pressure.

Pressure has many practical applications. Wide tyres are used in tractors to reduce pressure on the ground, while pointed nails produce greater pressure because their tips have a very small area. Understanding pressure helps us explain many natural phenomena and design useful tools and structures.

A. Short-Answer Questions

  1. What is pressure? Write its SI unit.
  2. How does the area of contact affect pressure when force remains constant?
  3. Why does a sharp knife cut more easily than a blunt knife?
  4. Why are dams made thicker at the bottom than at the top?
  5. Why are tractor tyres made wider than ordinary vehicle tyres?

B. Multiple-Choice Questions

1. Which formula represents pressure?
A. P=F×A
B. P=F/A
C. P=A/F
D. P=F+A

2. The SI unit of pressure is:
A. Newton
B. Joule
C. Pascal
D. Watt

3. If the same force acts on a smaller area, the pressure:
A. decreases
B. increases
C. remains the same
D. becomes zero

4. Liquid pressure generally increases with:
A. decrease in depth
B. increase in depth
C. decrease in density only
D. surface area only

5. Wide tyres of tractors are used mainly to:
A. increase pressure on the ground
B. decrease pressure on the ground
C. increase the weight of the tractor
D. increase the speed of the tractor


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