List-I | List II | ||
---|---|---|---|
A. | Phenol-formaldehyde resin | I | Glyptal |
B. | The copolymer of 1,3-butadiene and styrene | II | Novolac |
C. | Polyester of glycol and phthalic acid | III | Buna-S |
D. | Polyester of glycol and terephthalic acid | IV | Dacron |
A bob of heavy mass \(m\) is suspended by a light string of length \(l\). The bob is given a horizontal velocity \(v_0\) as shown in figure. If the string gets slack at some point P making an angle \( \theta \) from the horizontal, the ratio of the speed \(v\) of the bob at point P to its initial speed \(v_0\) is :
Neoprene is formed from chloroprene. It is prepared by free radical polymerisation. The monomer of neoprene is chloroprene. It is used for preparing gaskets, conveyor belts etc.