Vertical displacement of a plank with a body of mass m on it is varying according to law
y = sin ω t + √(3)cos ω t.
The minimum value of ω for which the mass just breaks contact with the plank and the moment it occurs first after t = 0, are given by
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Loss of contact occurs when downward acceleration equals g.
Step 1: Resultant displacement:
y = 2sin(ω t + (π)/(3))
Step 2: Maximum downward acceleration:
amax = 2ω²
Step 3: For loss of contact:
2ω² = g ⟹ ω = √((g)/(2))
Step 4: First occurrence after t=0:
ω t + (π)/(3) = (3π)/(2)
⟹ t = frac√(2)π6√(g)