A plank with a box on it at one end is gradually raised about the other end. As the angle of inclination with the horizontal reaches 30°, the box starts to slip and slides 4.0 m down the plank in 4.0 s. The coefficients of static and kinetic friction between the box and the plank will be, respectively : <br>

Question

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( A ) 0.6 and 0.5
( B ) 0.6 and 0.6
( C ) 0.4 and 0.3
( D ) 0.5 and 0.6