List I | List II | ||
---|---|---|---|
A | Pterophyllum | I | Hag fish |
B | Myxine | II | Saw fish |
C | Pristis | III | Angel fish |
D | Exocoetus | IV | Flying fish |
List-I | List-II | ||
A | Rhizopus | I | Mushroom |
B | Ustilago | II | Smut fungus |
C | Puccinia | III | Bread mould |
D | Agaricus | IV | Rust fungus |
A block of certain mass is placed on a rough floor. The coefficients of static and kinetic friction between the block and the floor are 0.4 and 0.25 respectively. A constant horizontal force \( F = 20 \, \text{N} \) acts on it so that the velocity of the block varies with time according to the following graph. The mass of the block is nearly (Take \( g = 10 \, \text{m/s}^2 \)):
A wooden block of mass M lies on a rough floor. Another wooden block of the same mass is hanging from the point O through strings as shown in the figure. To achieve equilibrium, the coefficient of static friction between the block on the floor and the floor itself is