Q. A horizontal plank has a rectangular block placed on it. The plank stars oscillating vertically and simple harmonically with an amplitude of 40 cm. the block just loses contact with the plank when the later is momentary at rest. Then
A) the period of oscillating is $2\pi/5\ \ $s
B) The block weighs double its weight when the plank is at one of the positions of momentary at rest.
C) the block weight 1.5 times its weight on the plank half way down
D) The block weights its true weight on the plank, when the latter moves fastest
Explanation
The correct answer is Option B: The block weighs double its weight when the plank is at one of the positions of momentary at rest..
A detailed explanation for this question is being prepared.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.