Q3. A 2 kg brick begins to slide over a surface which is inclined at an angle of $45 ^ { \circ }$ with respect to horizontal axis. The co-efficient of static friction between their surfaces is:\\
(1) 1.7\\
(2) $\frac { 1 } { \sqrt { 3 } }$\\
(3) 0.5\\
(4) 1