CLASS 8
LESSON- PRESSURE
1. . What is the pressure exerted by a girl weighing 400 newton standing on one `stiletto` heel of area 1cm2(=1/10,000 m2)?
2.  An elephant weighing 40,000 newton stands on one foot of area 1000 m2(=1/10 m2).

What pressure is exerted on the ground?

3.Why do deep-sea divers have to wear special suits before going for diving at the depths?

4.Complete the following sentences:

a. If two equal forces act in the opposite directions on an object, the net force acting on it is __________.

b. It is easier to cut with a sharp knife than with a blunt one because ________________________ ____________________.

c. Porters place a round piece of cloth on their heads, when they have to carry heavy loads because __________________________________________________.

.5 Give reasons-

(a) Buildings have wide foundations.

(b) It is easier to hold a school bag with wide straps than the one with thin strings.

(c) A bottle gets crushed when all its air is removed.

6.  State the relation between pressure exerted and area of the surface.