Gravitation — Science STD 9 — Question

Name the disease caused by mercury pollution of water.

Illustrate the law of conservation of energy by discussing the energy changes which occur when we draw a pendulum bob to one side and allow it to oscillate. Why does the bob eventually come to rest? What happens to its energy eventually? Is it a violation of the law of conservation of energy?

Which organelle is the “power plant” of eukaryotic cell. Write in brief its functions.

What are medullated nerve fibres?

Name two classes of chordates in which clawed digits are present.

Justify “Dust is a pollutant”?

Write any two observations which support the fact that atoms are divisible.