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Question:

Two fixed frictionless inclined planes making angles of 30° and 60° with the vertical are shown in the figure. Two blocks A and B are placed on the two planes. What is the relative vertical acceleration of A with respect to B?

4.9ms⁻² in horizontal direction

4.9ms⁻² in vertical direction

9.8ms⁻² in vertical direction

zero

Solution:

mgsinθ = ma ∴ a = gsinθ where a is along the inclined plane ∴ vertical component of acceleration is gsin²θ ∴ Relative vertical acceleration of A with respect to B is g[sin²60° - sin²30°] = g/2 = 4.9m/s² in vertical direction