What is the pressure exerted by a boy

weighing 80kg on the ground when he stands

on his feet whose area is 200cm2 ?

A. 80 pa

B. 1600 pa

C. 40,000 pa

D. 400 pa

The answer is C. 40,000 pa

Explanation:

Given

Mass ( m) = 80 kg

Area ( A) = 200 cm^2

= 0.02 m^2

g = 10 m/s^2

First calculating Force (F)

= m * g

= 80 * 10

= 800 N

Now

Pressure (P) = F/ A

= 800/0.02

= 40,000 pa

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.