Threee blocks A, B, C each of 1 kg mass are resting on a rough table. The contact area of each block is a square. The contact areas of the blocks are 1 cm², 2 cm², 3 cm² respectively. The blocks are of the same material and their contact forces have same surface roughness. When the same forces are applied on the blocks, the magnitude of friction forces in descending order will be

1. A, B, C
2. C, A, B
3. A, C, B
4. friction forces on all blocks will be equal.

If the resultant of the friction force and normal force makes an angle of 30⁰ from the friction force, the co-efficient of friction is

1. 
2. 
3. 
4.