A boy finds that he can use a uniform plank of wood for a seesaw if he tries to balance it
2 m from the end using a tree trunk as the
pivot. If the boy sits at the end of the shorter
side, the plank will balance the boy's weight.
If the plank is 7 m long and weighs 500 N.
What is the weight of the boy? ​

if they have a finite resultant

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.