An iron bar falling vertically thorugh the hollow region of a thick cylindrical shell made of copper expereinces a retarding force. What can you conclude about the iron bar?

The following real numbers have decimal expansions as given below. In each case decide whether they are rational or not.If they are rational, and of the form p/q what can you say about the prime factors of q ? : 0.bar54

The following real numbers have decimal expansions as given below. In each case, decide whether they are rational or not. If they are rational, and of the form p/q , what can you say about the prime factors of q ? :- 43.bar123456789

The following real numbers have decimal expansions as given below. In each case decide whether they are rational or not.If they are rational, and of the form p/q what can you say about the prime factors of q ? : 0.003bar352 .

A 70 kg man stands in contact against the ineer wall of a hollow cylindrical drum of radius 3 m rotating about its vertical axis with 200 rev//min . The coeffcient of friction between the wall and his clothing is 0.15. What is the minimum rotational speed of the cylinder to enable the man of remain stuck to the wall ( without falling) when the floor ids suddenly removed?

You have a bag of cotton and an iron bar, each indicating a mass of 100 kg when measured on a weighing machine. In reality, one is heavier than other. Can you say which one is heavier and why ?